CAUFDRNIA FBH^GAME "CONSERVATION OF WILD LIFE THROUGH EDUCATION" California Fish and Game is published quarterly by the California Department of Fish and Game. It is a journal devoted to the conservation and understanding of fish and wildlife. If its contents are reproduced elsewhere, the authors and the California Department of Fish and Game would appreciate being acknowledged. Subscriptions may be obtained at the rate of $10 per year by placing an order with the Editor, California Department of Fish and Game, 1416 Ninth Street, Sacramento. CA 95814. Checks or money orders in U.S. dollars should be made out to: California Fish and Game. Inquiries regarding paid subscriptions should be directed to the Editor. Complimentary subscriptions are granted on an exchange basis. California Department of Fish and Game employees may request complimentary subscriptions to the journal. Please direct correspondence to: Dr. Eric R. Loft, Editor-in-Chief California Fish and Game 1416 Ninth Street Sacramento, California 95814 u VOLUME 80 SPRING 1994 NUMBER 2 Published Quarterly by STATE OF CALIFORNIA THE RESOURCES AGENCY DEPARTMENT OF FISH AND GAME -LDA- STATE OF CALIFORNIA PETE WILSON, Governor THE RESOURCES AGENCY DOUGLAS P. WHEELER, Secretary for Resources FISH AND GAME COMMISSION Frank D. Boren, President Doug McGeoghegan, Member Richard Thieriot, Member Gus Owen, Member Robert R. Treanor, Executive Director DEPARTMENT OF FISH AND GAME BOYD GIBBONS, Director John H. Sullivan, Chief Deputy Director Al Petrovich Jr., Deputy Director Banky E. Curtis, Deputy Director Perry L. Herrgesell, Ph.D., Cliief Bay-Delta Division Rolf Mall, Ctiief Marine Resources Division Tim Farley, Cliief Inland Fisheries Division Terry M. Mansfield, Ctiief Wildlife Management Division John Turner, Chiief Environmental Services Division Susan A. Cochrane, Ctiief Natural Heritage Division DeWayne Johnston, Chief Wildlife Protection Division Richard Elliott, Regional Manager Redding Ryan Broddhck, Regional Manager Rancho Cordova Bhan F. Hunter, Regional Manager Yountville George D. Nokes, Regional Manager Fresno Fred Worthley, Regional Manager Long Beach CALIFORNIA FISH AND GAME 1994 EDITORIAL STAFF Eric R. Loft, Editor-in-Chief Wildlife Management Betsy C. Bolster, Ralph Carpenter, Arthur C. Knutson, Jr Inland Fisheries Dan Yparraguirre Wildlife Management Steve Crooke, Doyle Hanan, Jerome D. Spratt Marine Resources Donald E. Stevens Bay-Delta Peter T. Phillips Environmental Services CONTENTS Relationship Between Sea Otter Range Expansion and Red Abalone Abundance and Size Distribution in Central California .... Fred Wendell 45 The Effect of Different Han/est Methods on Sea Palm {Postelsia palmaeformis) Sporophyll Growth Peter E. Kalvass 57 Duck and Shorebird Reproduction in the Grasslands of Central California Roger L Hothem and Daniel Welsh 68 Roosevelt Elk Dietary Quality in Northern Coastal California Peter J. Gogan and Reginald H. Barrett 80 NOTES A Portable Field Sampling Table for Dock-side Sampling of Fish .... Robert R. Leos 84 CALIFORNIA FISH AND GAME Calif. Fish and Game (80)2:45-56 1 994 RELATIONSHIP BETWEEN SEA OTTER RANGE EXPANSION AND RED ABALONE ABUNDANCE AND SIZE DISTRIBUTION IN CENTRAL CALIFORNIA FRED WENDELL Marine Resources Division California Department of Fish and Game 213 Beach Street Morro Bay, CA 93442 Red abalone population surveys were conducted near Point Estero, California between 1 965 and 1 993, before, during, and after reoccupation of the area by sea otters. A decline in abalone density occurred (0.1 01 /m^ to 0.007/m^) associated with the reoccupation of the area by sea otters. Evidence is presented suggesting that sea otter predation was responsible for the decline and subsequent stability at densities below those needed to support a viable commercial or recreational fishery. INTRODUCTION Sea otters (Enhydra lutris) were over-exploited throughout the North Pacific rim during the 18"' and 19"" century fur trade era (Ogden 1941). Only a few remnant colonies survived that era, with as few as 50 sea otters surviving in California (Kenyon 1969). Many of the colonies are gradually expanding their range under protection of both state and federal law. Range expansion in California has coincided with the loss of commercial and recreational shellfish fisheries (Wild and Ames 1974, Miller et al. 1975, Wendell et al. 1986). Although sea otter effects on nearshore marine community structure are generally recognized (McLean 1962, Estes and Palmisano 1974, Dayton 1975, Foster et al. 1 979, Duggins 1 980), their effects on shellfish fisheries have been controversial (Estes and VanBlaricom 1985). The controversy exists because of the difficulty in assessing the magnitude of the effects of sea otter predation and human harvest in the loss of fisheries. A historical review of shellfish fisheries beyond the sea otter's range emphasized their loss from over-exploitation (Estes and VanBlaricom 1985). The review expressed doubts about the relative effects of human harvest and sea otter predation in the loss of the central California red abalone fishery. The sport and commercial red abalone fisheries in central California were the first to experience competition with foraging sea otters. Most of the research that focused on the relationship between sea otters and abalone abundance lacked information on pre-reoccupation densities. The earliest research assessed sea otter effects by comparing abalone abundance between areas with and without sea otters (Ebert 1968). Most subsequent research focused on population dynamics over longer time periods within small study areas already occupied by sea otters (Lowry and Pearse 1973, Cooper et al. 1977, Hines and Pearse 1982, Ostfeld 1982). 45 46 CALIFORNIA FISH AND GAME Here, data on abalone abundance and size distribution are analyzed that were collected intermittently over a long time period that included both pre- and post- reoccupation intervals within a relatively large study area. The original objective of the study was to monitor abalone abundance and population structure in an area important to the commercial fishery. After the loss of the fishery, the objective changed to monitoring the immediate and long-term effects of sea otter predation on abalone abundance and population structure (E. Ebert, California Department of Fish and Game, pers. comni.). METHODS The Point Estero study area (lat 35 3()'N, long 121 02'30"W) is approximately 20 km north of Morro Bay, California (Fig. 1 ). The area is characterized by low profile reefs, averaging 2 to 3 m high, aligned nearly perpendicular to the shoreline and spaced about 1 5 to 60 m apart. Interspersed are gullies or pavement-like substrate strewn with cobbles and boulders. Sand intrusions frequently isolate rocky outcroppings, particularly Figure 1 . Spatial relationship of the Point Estero red abalone study area (darkened area) and location of the southernmost sea otter rafting site (circles) by selected year. Sampling strata shown in lower left insert. RELATIONSHIP BETWEEN SEA OTTER AND RED ABALONE 47 in shallower depth zones. Ocean depths within the 2.4 km long by 0.8 km wide study area ranged from 5.5 m to 22.0 m. The area was divided into five strata arranged from south to north (Fig. 1 ). Strata boundaries were selected to provide comparable depth distributions among strata. Each strata was divided into sampling units (transect areas) measuring 4.6 x 30.5 m each. Four of the strata (II-V) each contained 3,750 sampling units. Strata I contained 3,000 sampling units. Thus, the entire study area was potentially available for sampling. Sampling effort was evenly distributed among strata and transects were selected randomly within strata. Each potential sampling unit was numbered and a random number generator was used to select those to be sampled. Initially, 15 transects were sampled per annual survey (3/strata). In 1967, the annual sampling effort was increased to 25 transects. Transects were located using triangulation from existing and fabricated shoreline markers and laid on a 290 bearing (i.e., parallel to the shore line). Abalone were identified by species when possible and counted by SCUBA divers. Some abalone, particularly those observed within narrow crevices, were not identifiable. Species other than red abalone (Haliotis rufescens) were present in very small numbers and when identified were excluded from data analysis. Accessible individuals were removed and measured to the nearest millimeter across the longest dimension of the shell and replaced within the transect area. The sizes of inaccessible individuals were visually estimated and assigned to one of three size groups (< 1 02, 1 02- 1 96, > 1 96 mm). Population estimates were generated based on a simple random sampling design. Estimates are calculated by multiplying the mean count per transect by the potential number of transects within the survey area. Sea otter densities and spatial distributions were assessed using aerial survey data. Emphasis, for this paper, was placed on aerial surveys conducted during the period when sea otters expanded their range into the vicinity of the study area. Range expansion in California has typically been defined by changes in the location of the southern- and northern-most large sea otter raft. However, a range boundary identified by this criterion does not recognize that foraging activity occurs beyond the raft location. Foraging activity can be located several miles beyond the raft site (Wild and Ames 1974). Prey selection by sea otters was assessed using data collected during a food habit study conducted within the Point Estero area in 1971 and 1972 (Wild and Ames 1974). Observations were made from shore using telescopes ranging from 15x to 60x. Food items were identified to the lowest taxon possible. RESULTS Surveys were conducted in 1965, 1966, 1967, 1970, 1971, 1973, 1974, 1978, and 1993. A total of 205 transects were sampled during the nine surveys. The proportion of sand on a transect and the water depth were covariates in the study design. For all survey years combined, both showed statistically significant negative correlations 48 CALIFORNIA FISH AND GAME with red abalone abundance (Spearman rank (/) values of -0. 1 76, F <0.05 and -0.326, P < 0.0 1 , respectively). However, no temporal trends were apparent in the distribution of transect substrate types (r = 0.054, P > 0.05 ) or depths (r = 0. 1 29, A* > 0.05 ) through the study period. The test for heterogeneity of slopes among years in an analysis of covariance showed water depth (P = 0.0096) and proportion of sand (P = 0.0025) to be heterogeneous among years. There was a temporal trend in the abundance of red abalone within the study area; the estimated population size declined through time (Table 1 ). There was a statistically significant negative correlation (/• = -0.901, P < 0.01) between median red abalone counts and survey year. The main effect of survey year in the analysis of covariance was highly significant {P < 0.0005). Both mean red abalone count per transect and mean counts adjusted for the covariates declined rapidly starting in 1967 (Fig. 2). The average red abalone density prior to 1967 was 0.100 abalone/m-, declined to 0.010 abalone/m- by 1973, and remained below that level for all subsequent surveys (Table 1 ). A Kruskal-Wallis multiple pairwise comparison showed counts from all years after 1973 to be significantly different from those that preceded at an experimentwise error rate of 0. 1 5. Some pairs comparing 1971 with earlier years were also significantly different. The estimated red abalone population size within the study area decreased by 84 percent within six years, and stabilized within eight years at seven percent of the initial ( 1 965 ) estimate (Fig. 3 ). The population estimates during 1 978 and 1 993 suggest that the resource remained relatively unchanged during the 19-year period from 1974 to 1993. The decline in abundance appears to have occurred progressively from north to south within the study area. The mean count declined below 10 abalone/transect between the 1965 and 1966 surveys within the northernmost strata (V), followed progressively within strata IV (after 1966), strata III ( 1 967), and strata's II and I ( 1 970) (Fig. 4). Although multiple pairwise comparisons between years within strata did demonstrate differences between pairs, the resolution was not sufficient to place Table 1 . Red abalone density (/m-) and estimated population size within the Point Estero study area by survey year. Transects Mean Population estimate Year sampled density (S.E.) (2,508,391 m-) 1965 15 0.1010(0.0316) 253,350 1966 15 0.0995(0.0257) 249,600 1967 25 0.0718(0.0147) 180,100 1970 25 0.0606(0.0116) 152,000 1971 25 0.0166(0.0037) 4 1 ,650 1973 25 0.0103(0.0043) 25.850 1974 25 0.0066(0.0026) 16,550 1978 25 0.0055(0.0017) 13,800 1993 25 0.0072 (0.0026) 18,050 RELATIONSHIP BETWEEN SEA OTTER AND RED ABALONE 49 O < 13 o o Ul < m < < 15 10- 5- ii 6.\ «. O O MEAN COUNT • • ADJUSTED MEAN 64 69 74 '•••-O I I I I I I I I I I I I I I I 79 84 89 94 YEAR Figure 2. Mean red abalone count per transect and mean count adjusted for covariation between years in distribution of transect depth and substrate type. O A O o o o r: 3-1 2 N (/I 3 a. o Q. First Year S«a Otters Foraged within Study Area 'I -1 T 64 69 74 79 f 1 f I T I 84 89 94 YEAR Figure 3. Estimates of red abalone population size (95% CI) within the Point Estero study area through time. 50 CALIFORNIA FISH AND GAME statistical significance to the temporal and geographic patterns within strata. The size frequency distribution of red abalone within the Point Estero study area remained relatively unchanged through 1 978. No abalone were accessible for measuring in 1993. There were no statistically significant differences in the size frequency distributions ofmeasured abalone in pairwise comparisons (Kolmogorov-Smimov 2- sample tests). The mean sizes ofmeasured abalone ranged from a high of 181 mm in 1971 to a low of 155 mm in 1978 (Fig. 5). There were also no statistically significant temporal trends in the proportion of abalone within size groups (/; sm = 0.283, P > 0.05; /; med = -0.2 \1,P> 0.05; and /; Ig = -0.333, P > 0.05). However, the proportion of abalone in the 1993 survey within the smallest size group (< 1 02 mm ) was higher than on any prior survey and there w ere proportionally fewer large abalone (> 196 mm). Reoccupation of the Point Estero region by sea otters occurred through southward range expansion between 1967 and 1971 (Fig. 1). Sea otters were first observed foraging within the study area in 1967 (E. Ebert, CDFG, pers. comm.). The range expanded beyond Point Estero to Cayucos in 1 972. In the interim, the peripheral male STRATA 5 ^-f- I I I I I I STRATA 4 -f-f- T 1— T 1 — I — I — r I I STRATA 3 ■♦^ I I I I I — I— I — I— r 20 10 I 1 I I I I I STRATA 2 • • 1 — I — I ▼ I — r— T- T — r I I I STRATA 1 • ^ • -I — I — r I I r I I 60 ^-1 — I — 1 I T — I — r— T — I I I — r—r 74 79 84 94 YEAR Figure 4. Mean red abalone count per transect (S.E.) by strata and survey year. Shaded area includes surveys with mean counts >10 abalone/transect. RELATIONSHIP BETWEEN SEA OTTER AND RED ABALONE 51 group actively foraged in the vicinity of the Point Estero study area. There are no direct measures of changes in foraging pressure within the study area during this time period. However, aerial counts of sea otters within the southern peripheral portion of the range between 1968 and 1972 varied considerably (Table 2). The variation in counts followed a seasonal pattern, with high counts between January and July and relatively low counts during the remaining months. The highest count each year ranged from 62 in 1968 to 187 in 1971. Sea otter food habit observations collected within the vicinity of the Point Estero study area in 1971 and 1972 documented a marked shift to the use of a broad forage base (Wild and Ames 1974). In 1971, red abalone comprised almost 60 percent by number of the food items observed being consumed by sea otters. In 1972, that proportion had declined to less than 2 percent (Fig. 6). DISCUSSION The Point Estero surveys documented a precipitous decline in abalone abundance between 1967 and 1971. This decline coincided with the reoccupation of the area by sea otters. This coincidence suggests that sea otters could have caused the decline, particularly since sea otters were actively feeding on abalone through 1 97 1 . However, abalone populations have also declined in areas outside of the sea otter's range. Declines in these areas have been attributed to such factors as over-exploitation (Estes and VanBlaricom 1985) and disease (Haaker et al. 1992). 200 190 ? 180 E 170 1— o z LJ 160 150 140 < LJ 2 130 120 110 100 SURVEY YEAR Figure 5. Mean red abalone size (S.E.) by survey. 52 CALIFORNIA FISH AND GAME Table 2. Number of sea otters observed at the southern range periphery by area during aerial surveys. 1 968 through 1 972. Area I = Cambria to White Rock, Area 2 = White Rock to Cambria Radar Station. Area 3 = Radar Station to Point Estero, and Area 4 = South of Point Estero. Total count Percent within Date Area 1 Area 2 Area 3 Area 4 8 Nov 68 62 85 13 2 0 20 Dec 68 34 97 3 0 0 3 1 Jan 69 117 0 98 2 0 10 Feb 69 100 2 98 0 0 10 Mar 69 129 57 43 0 0 7 Apr 69 73 0 23 77 0 5 May 69 41 5 80 15 0 2 Jun 69 40 10 80 10 0 1 Aug 69 59 5 81 14 0 8 Sep 69 26 58 42 0 0 6 Oct 69 43 2 89 9 0 1 Dec 69 41 2 66 32 0 7 May 70 165 95 0 0 5 17 Sep 70 45 20 78 2 0 13 Feb 71 60 8 10 82 0 16 Apr 71 162 4 94 2 0 1 Jul 71 187 11 58 29 2 5 Oct 7 1 86 6 62 24 8 4 Jan 72 75 5 13 82 0 19 Apr 72 91 11 6 2 81 "^Study area 1 ocated within Area 3. The commercial red abalone fishery had operated continuously within the Point Estero area since the early 193()'s. Morro Bay was the primary port of landing for red abalone taken from this area. Landings there remained relatively stable for decades then decreased rapidly over a short period of time. However, the decline occurred more slowly than that observed within the Point Estero study area ( Fig. 7 ). Red abalone resources in the region supported a commercial harvest through 1978. Fishing effort was gradually concentrated into a smaller area as it shifted southward into less productive habitat south of Morro Bay. Sea otters expanded their range beyond this area into the Pismo Beach area in 1978. Commercial abalone fishing can be excluded as a probable cause for the precipitous decline in abalone density observed within the Point Estero area for two primary reasons: I ) the decline occurred across all size classes of abalone, even though the minimum commercial red abalone size limit is 197-mm. and 2) the decline appears to have occurred sequentially from north to south in a relatively restricted geographical area compared to the range of operation typical of the fleet. Furthermore, it is improbable that a fishery-caused decline would coincide exactly with the reoccupation of the area by sea otters. RELATIONSHIP BETWEEN SEA OTTER AND RED ABALONE 53 tr 111 m ui a. 60 50 40 30 20 10 0 S e 1 a c ■ .1 11 o o o a o o 8 I c ^ 1971 (n = 82) ZZZl 1972 (n = 52) ■ a lo I e o a 00 JO E u PREY Figure 6. Changes in sea otter prey selection in vicinity of Point Estero between 1 971 and 1 972. o o. o o o X UJ o -J < 09 < o UJ MORRO BAY COMMERCIAL LANDINGS 80 85 90 YEAR Figure 7. Commercial red abalone landings at Morro Bay from 1960 through 1992. 54 CALIFORNIA FISH AND GAME No evidence exists to suggest that illegal take changed appreciabl) during this time period despite the focused law enforcement effort generated by the controversy. It also seems probable that abalone densities would have increased in the absence of fishing pressure (especially after 1970, Fig. 2) if that pressure was the causative agent in the initial decline. No such population growth has been observed in the two decades following the collapse of the fishery. Disease can be excluded as the probable cause for the observed decline because of a lack of evidence given considerable research diving and commercial activity in the area. Moreover, abalone were found only in narrow crevice habitat in every survey conducted after the area was reoccupied by sea otters. It seems improbable that survivors from a widespread disease would be limited to this microhabitat. Changes in habitat can also be excluded since analysis demonstrated that appreciable habitat modifications or sampling biases had not occurred. The density of red abalone within the Point Estero study area stabilized within a few years of the initial reoccupation of the area by sea otters (0.007/m-). This density is similar to the abalone densities reported in several studies conducted within the long-established sea otter range (Ebert 1968, North 1965) and is low enough to preclude commercial effort and limit recreational harvest to a few knowledgeable individuals. Higher abalone densities have been reported within reoccupied habitat, but. they occurred in particularly crevice-rich habitat (Lowry and Pearse 1 973, Cooper et al. 1977, Hines and Pearse 1982). The temporal and geographical pattern of decline in shellfish abundance is comparable to that reported for Pismo clams when sea otters reoccupied beaches with clams in Monterey Bay (Miller et al. 1975, Stephenson 1977) and Pismo Beach (Wendell et al. 1986). The documented loss of shellfish fisheries associated with sea otter reoccupation strongly suggests the pattern can be used to predict future losses wherever sea otter range expansion occurs. MANAGEMENT IMPLICATIONS This study provides quantitative documentation of large-scale depletion of abalone stocks directly attributable to the foraging activities of sea otters. This conclusion supports the view that socioeconomic benefits derived from recreational and commercial shellfish fisheries that have developed in the absence of .sea otters will largely be lost through sea otter range expansion. However, there are also other positive effects associated with sea otter range expansion. Algal production has been observed to increase in many areas reoccupied by sea otters due to the reduction in abundance of herbivorous macroinvertebrates (North 1965, Estes and Palmisano 1974, Duggins 1980). Although evidence is generally lacking, these increases presumably can, in turn, infiuence the abundance of finfish populations that are limited by a lack of habitat or forage provided by algae. Sea otter range expansion also decreases the risks the population faces from human activities, particularly from large-scale oil spills, and increa.ses the opportunities for observing sea otters. RELATIONSHIP BETWEEN SEA OTTER AND RED ABALONE 55 Ongoing debate focuses on the possibility of limiting sea otter distribution while insuring a secure future for sea otters and providing for human use of shellfish resources. If both concerns are to be provided for, the reoccupation of the sea otter's natural range would have to be limited through zonal management. ACKNOWLEDGMENTS This study, with a temporal scope covering almost 3 decades, draws upon the research efforts of a great many individuals. I acknowledge the extensive contributions made by the previous principle investigators K. Cox ( 1 964), R. Poole ( 1 965), E. Ebert ( 1 966 - 1 967), and R. Burge ( 1 970 - 1 978) and thank them for their efforts. I thank D. Gotshall, P. Wild, S. Schultz, J. Duffy, J. Ames, R. Hardy, and C. Pattison for their in- water efforts. I also thank N. Abramson and P. Law for their help in the statistical analysis of the data. P. Wild, R. Heimann, and anonymous referees provided advice and a critical review. To all of the above and those not mentioned, my thanks. LITERATURE CITED Cooper, J.. M Wieland, and A. Hines. 1977. Subtidal abalone populations in an area inhabited by sea otters. Veliger 20:163-167. Dayton. P. 1 975. Experimental studies of algal canopy interactions in a sea otter dominated kelp community at Amchitka Island. Alaska. Fish. Bull. 73:230-237. Duggins, D. 1980. Kelp beds and sea otters: an experimental approach. Ecol. 61:447-453. Ebert, E. 1968. California Sea Otter - Census and Habitat Survey. Underwater Naturalist. Winter 1968:20-23. Estes, J., and J. Palmisano. 1974. Sea otters: their role in structuring near shore communities. Science 185:1058-1060. , and G. VanBlaricom. 1 985 . Sea otters and shellfisheries. Pages 1 87-236 in Beddington, J.. R. Beverton, and D. Lavaigne (eds.). Marine Mammals and Fisheries. Allen and Unwin, London. Foster M., R. Cowen, C. Agegian, D. Rose, R. VanWagenen, and A. Hurley. 1979. Continued studies of the effects of sea otter foraging on kelp forest communities in central California. Calif. Fish and Game contract rpt. #S-1 156, 107 p. Haaker, P., D. Richards, C. Friedman. G. Davis, D. Parker, and H. Togstad. 1992. Mass mortality and wither syndrome in black abalone. Haliotis cracherodii, in California. Pages 2 14-224 in Shepherd. S., M. Tegner, and S. Guzman del Proo (eds). Abalone of the World: biology, fisheries and culture. Fishing News Books, New York. Hines, A., and J. Pearse. 1982. Abalones. shells, and sea otters: Dynamicsof prey populations in Central California. Ecology 63:1547-1560. Kenyon, K. 1 969. The sea otter in the easter Pacific Ocean. North American Fauna 68: 1 -352. Lowry. L., and J. Pearse. 1 973. Abalones and sea urchins in an area inhabited by sea otters. Mar. Biol. 23:213-219. McLean, J. 1962. Sublittoral ecology of kelp beds of the open coast areas near Carmel, California. Biol. Bull. 122:95-1 14. Miller, D.. J. Hardwick, and W. Dahlstrom. 1975. Pismo clams andsea otters. Calif. Fish and Game, Mar. Resources Tech. Rep. 3 1 , 49 p. 56 CALIFORNIA FISH AND GAME North. W. 1965. Kelp habitat improvement project: urchin predation. 1964-1965 Annual Rep. Calif. Institute Tech. Ogden. A. 1941. The Cahfornia sea otter trade, 1784-1848. University of Cahfornia Press, Berkeley. 25 1 p. Ostfeld. R. 1 982. Foraging strategies and prey switching in the California .sea otter. Oecologia 5.^:170-178. Stephenson, M. 1977. Sea otter predation on Pismo clams in Monterey Bay. Calif. Fish and Game 63: 1 17-120. Wendell. F.. R. Hardy. J. Ames, and R. Burge. 1 986. Temporal and spatial patterns in sea otter, Euhxdia lufris, range expansion and in the loss of Pismo clam fisheries. Calif. Fish and Game 72: 1 97-2 1 2. Wild. P. and J. Ames. 1974. A report on the sea otter, Enhydra liilris L., in California. Calif. Fish and Game. Mar. Resources Tech. Rep. 20. 93 p. Received: 1 April 1994 Accepted: 22 July 1994 CALIFORNIA FISH AND GAME Calif. Fish and Game (80)2:57-67 1 994 THE EFFECT OF DIFFERENT HARVEST METHODS ON SEA PALM {POSTELSIA PALMAEFORMIS) SPOROPHYLL GROWTH PETER E. KALVASS California Department of Fish and Game Marine Resources Division 19160 S. Harbor Dr. Fort Bragg, CA 95437 Sea palm {Postelsia palmaeformis) is an erect annual brown alga occurring along the central and northern coasts of California in high intertidal areas subject to heavy wave shock. Presently, there is no restriction on the amount or method by which sea palm can be commercially harvested. In spring 1989, we initiated a study to compare the effects of three different harvest methods on several growth and development parameters. A factorial experimental design was chosen to examine sporophyll (blade) growth under the three treatments over a 4 month period. Treatments included blade cut in which only blades are taken, branch cut in which the rounded portion of the sporphyll is also removed, and stipe cut in which the the meristem and fruiting portion of the sporophyte is taken, as well as a control group. Monthly incremental blade growth was significantly different among treatments {P< 0.000), with the blade cut group exhibiting the fastest growth rate. Mean blade length increased 7.5 times in two months from the start of the experiment for the blade cut group, compared to a 1 7 percent increase for the control group for the same time period. We conclude that a harvest method similar to the blade cut treatment would have the benefit of allowing multiple yields of sporophylls in a season, ensure spore production, and reduce aesthetic degradation in comparison to the other harvest methods examined. INTRODUCTION In the spring of 1989 the potential for large-scale removals of sea palm {Postelsia palmaeformis) by commercial kelp harvesters in central and northern California became apparent to the Department of Fish and Game (Department). Sea palm is locally abundant in the middle to high intertidal zone in exposed areas, such as rocky headlands subject to high wave shock, from central California to Vancouver Island (Abbott and Hollenberg 1976). A member of the Laminariales, the sporangial thallus of a sea palm sporophyte can grow to 60 cm (24 in.), standing erect and resembling a miniature version of its terrestrial namesake (Fig. 1 ). The plant attaches to rocky substrate by means of a hapteron, or holdfast, and is found patchily distributed usually among mussel (Mytilus spp.) beds (Dayton 1973). Sea palm is an annual and like all Laminariales exhibits alternating morphological phases, a microscopic gametophye and the large macroscopic sporophyte for which there is an active commercial fishery 57 58 CALIFORNIA FISH AND GAME during the spring to fall months in certain portions of its range. Presently, sea palm may not be taken in California under authorization of a sport fishing license (Title 14. Sec. 30. 10), though there is no limitation on the taking ofsea palm under a commercial kelp harvesting permit. Resolution of this legal anomaly was a motivating factor for this study. Preliminary investigation of the local sea palm fishery in Mendocino County, northern California, in 1989 included discussions with a harvester who claimed to harvest sea palm by removal of sporophylls (blades) only, leaving approximately 25 mm of the grooved portion of the blade intact on the plant. This was suggested as an Wire loop Plastic tie- wrap tags Figure 1 . Sea pa\m {Postelsiapalmaeformis) showing haptera, stipe, and sporophylls (from Abbott and Hollenberg 1976). HARVEST EFFECTS ON SEA PALM GROWTH 59 alternative to cutting the stipe, which destroys the thallus, a method which is legal and practiced by some harvesters. The blade cutting method allows the plant to remain alive while allegedly yielding as many as three crops during the spring to early fall growing season. It was unclear whether this method allowed the plant to produce spores for the next generation of gametophytes. Sporangia are first produced in late spring in linear sori lining grooves on the blades, with meiospores then released during low tides onto the adjacent rocky substrate. Blades become eroded after these fruiting phases (Abbott and Hollenberg 1976). The goal of this study was to determine the impact of the following three alternative harvest methods upon sea palm growth and spore development: I) complete blade removal; 2) partial blade removal; and 3) stipe cutting to remove the stipe apex and all branches (terete portion of blade) and blades. Impact variables to be measured were change in blade and stipe length over time, sporophyte density, and presence or absence of spore release. REEFS a 20.8- Postelsia Study Site Pt Cabrillo Marine Reserve 0 so 100 ISO i •00 230 1 Meters Postelsia study beds Lightnnuse 03 416 125 «12 Figure 2. Sea palm study site at Point Cabrillo Marine Reserve near Fort Bragg, California. 60 CALIFORNIA FISH AND GAME METHODS Beginning in May 1989, a sea palm bed was chosen for study at Point Cabrillo Marine Reserve (PCMR) about 10 kilometers south of Fort Bragg in Mendocino county (Fig. 2). PCMR is on an exposed rocky headland in which all forms of marine life are protected from harvest. The bed we chose is easily accessible from the mainland and though exposed to heavy surf, particularly at high tides, is partially protected by outer reefs. The study area was the northern edge of a main bed about 1 0 meters in length. The study was designed as a two-way analysis of variance (ANOVA) with treatments and elapsed time, expressed in monthly intervals, as the main effects. Four plots were chosen in the study area, each representing a portion of a discrete patch of sea palm, within close proximity to each other and subject to similar wave exposure. Plots were 0.5 m by 1 .0 m, delineated by means of a removable rectangle of pvc piping, with each plot representative of a separate treatment. The treatments included partial blade removal (blade cut) of all blades at a point approximately 25 mm (I in.) from the inceptionof grooves at the proximal end of the blade; complete removal of all blades at the junction of branch and blade (branch cut); partial stipe removal (stipe cut) in which the stipe was cut just below the apex containing all branches and blades; and a control group. All plants in each plot were counted and subjected to one of the four treatments. Eight plants, chosen at random from mature-appearing plants (all with stipe length > 1 70 mm ) in each plot, were tagged with numbered plastic tie-wraps around the stipe. Approximately 1 0 blades or branches of each tagged plant were isolated with plastic- coated wire looped through the group and around the plant's stipe so as to ensure that the same blades were measured throughout the experiment, thereby reducing the error variance component in monthly mean blade lengths (Fig. 1). Following treatment of all blades, blade measurements were made to the nearest millimeter, from the inception of grooves at the proximal end of the blade to the blade tip. Stipes were measured from the base at the junction of the haptcron and stipe to the apex immediately below the formation of branches. Stipe length measurements were not made on stipe cut plants during the study and no stipe lengths were recorded on branch cut plants in May. Measurements were made once each month from May through August 1989. Plots were relocated each month with the aid of photographs and pvc rectangles so that plant counts and measurements could be made. In May and June 1990, sporophylls of five plants in the same bed as in 1989 were tagged, given the blade cut treatment, and subsequently assessed for spore release. Plants were treated in May during a low spring tide and cut portions were retained for laboratory examination. Pieces were wrapped in sea water-soaked paper towels, stored overnight under refrigeration, and subsequently examined with a dissecting microscope for spore release the following day. In June, following a month of growth, sections of new blade were removed from four tagged plants and a control plant and examined as before. HARVEST EFFECTS ON SEA PALM GROWTH 61 RESULTS Blade Length Growth as expressed by elongation of blades was examined in two ways: cumulatively and incrementally. The control group mean bladelength was 238 mm (SD 54) at the start of the study, growing to 298 mm (SD 57) by August: an increase of 25% over the 98 day period (Table I, Fig. 3). Mean blade cut length in May was 26 mm (SD 7), increased rapidly to 112 mm by June (SD 24), and 195 mm (SD47) by July. By August only one plant, with a mean blade length of 335 mm (SD 75), remained. The branch cut treatment was expected to hinder growth because the sea palm meristem is intercalary, located between stipe and blade in the region where the branch was incised. Surprisingly, mean blade length was 84 mm (SD 57) in August for this group. By June all remaining sporophytes in the stipe cut group exhibited fractured stipes and no evidence of regrowth. The stipe cut group was not included in the blade length analysis. Incremental growth was defined as change in mean blade length for each plant between monthly measurements. Negative increments were coded as zero growth. A two-way ANOVA showed that the treatment effect was significant {P < 0.000), but month and interaction effects were not significant {P > 0. 18) (Table 2). The absence of significant interaction between the two main effects (as evidenced by the parallelism of the lines connecting the monthly means for each treatment in Fig. 3) increased the Table 1 . Sea palm blade length (mm) cell means by treatment and month. Treatment Control Blade Cut Branch Cut Month n X SD n X SD n A" SD May 75 238 54 87 26 7 0 June 76 279 70 83 112 24 29 11 6 July 40 278 76 80 195 47 27 38 28 August 30 298 57 10 335 75 33 84 57 Table 2. Two-way ANOVA of sea palm blade length (mm) increments by treatment and month. Source of Variation DF SS MS F Prob. TREATMENT 2 20314 10156.98 19.00 0.0001 ** MONTH 2 1917 958.42 1.79 0.1811 TREATMENT*MONTH 4 3311 827.72 1 .55 0.2092 Error 36 29222 Total 44 54764 R -Square = 0.649 62 CALIFORNIA FISH AND GAME usefulness of the other statistics (Nie et al. 1975). Interestingly, though the control group maintained a greater total mean length through most of the summer, the blade cut treatment group exhibited a faster rate of growth in each month (Fig. 4). In two of the three months, the branch cut group growth rate was greater than that of the control group (Fig. 5). There were several disruptive developments during the experiment. There was an unexpectedly high loss of sporophytes due to .stipe breakage or complete removal (presumably from wave shock) as well as the loss of identifying wire for some blade groups. In these cases, blade groups were chosen randomly among remaining undamaged blades. The reduction of numbers of plants during the experiment may have created an unexamined plant effect which could have been responsible tor some of the variance in blade growth. Additionally, blade erosion began with the onset of truiting, somewhat confounding the assessment of growth via blade elongation (Abbot and Hollenberg 1976). 500 400 300 X f— o UJ L^ 200 Q CD 100 CONTROL 0 Figure 3. Sea palm mean blade length by treatment and month. HARVEST EFFECTS ON SEA PALM GROWTH 63 E E 500 400 300 - 200 < m 100 0 iOO CONTROL y=151.22+19.03x R ^=0.29 I ^ 400 - E ^ 300 I— o < I en 200 100 0 500 430 E E X 300 t— o LJ - 200 LJ < ^ 100 0 BRANCH CUT y--214. 77 + 37. 05x R ^ =0.63 _ BLADE CUT y = -423. 31+89. 37x - R =0.92 / - 5 6 7 8 MONTH Figure 4. Regressions of sea palm blade length on month by treatment. 64 CALIFORNIA FISH AND GAME The site was revisited in September 1989. but no measurements were made. All treatment plots were partially submerged, with the blade cut group appearing healthy and comparable to the control group in blade length. There was significant growth noted on some of the branch cut sporophytes. Stipe Length Stipe elongation was monitored to assess whether blade removals would affect the rate of stipe growth, and evaluated by separate one-way ANOVAs with treatment and month as factors. Stipe lengths were significantly different between treatments (P < 0.0000), however, mean stipe lengths for the branch cut group were initially shorter than the control and blade cut groups (Table Is). A posteriori Scheffe tests showed the branch cut group to be significantly different from each of the other two groups (P < 0.0000). There was no significant difference between stipe lengths when examined by the month factor alone {P = 0.64). 120 100 E E z LU LU a: o X o z LU _l LU Q 5 CD MAY-JUN JUN-JUL JUL-AUG Figure 5. Sea palm mean blade length increments by treatment and month. BLADE CUT CONTROL BRANCH CUT HARVEST EFFECTS ON SEA PALM GROWTH 65 Table 3. Sea palm stipe length (mm) cell means by treatment and month. Treatment Control Blade Cut Branch Cut Month n X SD n x SD n .x~ SD May 8 367 35 8 345 40 0 June 4 412 16 7 444 28 5 229 42 July 4 431 53 8 434 54 4 248 52 August 3 427 16 1 460 0 4 251 51 Density Sporophyte counts were made each month within each 0.5 m- plot. Overall mean was 53.1 plants or 106.2/m-. The stipe cut plot suffered the greatest reduction in density - from 128.0 in May to 16.0/m- in August, a reduction of 87.5%. The branch cut plot suffered the lowest plant loss at 1 2.6% and began with the highest density at 1 72.0 plants/m-. The control group suffered a 49.0% loss rate compared to 74.0% for the blade cut group. The greatest percentage reduction occurred between July and August for each group other than the control group. Spore Release In May 1990, cut sporophylls of the five treated tagged plants were examined by dissecting microscope and zoospore release was noted for all five plants. In June, following a month of growth, sections of new blade were removed from four tagged plants and a control plant and examined as before. The control plant and two of the treated plants appeared to show zoospore release. By October 1990, no tagged plants remained and about 60% of the original bed was gone, presumably due to senescence and wave shock. DISCUSSION Results confirmed the anecdotal evidence of local kelp harvesters (Betsy HoUiday, pers.comm.) that proper blade cutting allows the production of at least one additional crop in a season, since, by July 20, mean blade length of the blade cut group (195 mm) approached that of the control group (278 mm). Spore production was also evident one month after blade cut treatment in 1990. The blade cut treatment elicited a strong recovery response and capacity for spore production, while branch cutting had a more limiting effect upon blade growth recovery. Nereocystis luetkeana, bull kelp, is another annual Laminarian. It exhibits rapid stipe elongation initially, then slows while stipe girth and blade growth accelerates. Blade growth appears to continue at a steady rate well into maturity (Nicholson 1970). Partial blade removal of all but 5 cm of bull kelp blade curtailed growth for the first 2 weeks, then growth increased to a rate at or above that of untreated plants. Nicholson (1970) believed that this method of partial blade removal would permit several blade crops per year from these annual 66 CALIFORNIA FISH AND GAME sporophytes. The sea palm uses a unique strategy to help create patches free of competitors on bare rock, its most suitable substrate. Pioneer sporophytes clear areas by attaching to mussels which can increase the chances of the mussels being torn loose by heavy wave action. In this way sea palm sporophytes can establish themselves in areas otherwise controlled by more dominant species (Dayton 1973). Sea palm bed boundaries can change within a season and from year to year, with new beds becoming established in suitable habitat (Paine 1988). However, Postelsia seems to have an effective sporophyte colonization distance of only about 3 m from the edge of an existing sea palm patch (Dayton 1973). In a Puget Sound study, only 369f of small patches ( 1-30 plants) continued to the following year, but all patches with more than 120 individuals persisted (Paine 1988). Local extinctions due to interaction with dominant perennial species such as Mytilus are inevitable, but probably transitory (Lawrence and McClintock 1988). Subsequent studies might examine sea palm recruitment success relative to the blade cut treatment while varying such elements as plot size and onset of harvest season. Based upon the four criteria used to assess harvest impact and our knowledge of Postelsia survival strategy, we conclude that the blade cut method is not a significant negative impact upon sporophyll growth and spore production. However, we did not investigate the volume or viability of spores produced following blade cutting. Regarding present management policy, it may be desirable to institute regulations permitting only the blade cut method of harvest, which would allow multiple yields, ensure spore production, and reduce aesthetic degradation in comparison to the existing regulation. Such benefits are offset, at least partially, by reduced harvest efficiency in comparison to the stipe cut method of harvest. However, the stipe cut group suffered the greatest loss of plant density, presumably because holdfasts require the translocation of photoassimilates from the sporophylls for growth (Schmitz and Lobban 1 976). In light of the limited spore dispersal of sea palm, clear-cut stipe cutting (removal of all plants over extensive portions of sea palm beds), particularly early in the reproductive season, may create an ' Allee effect', or negative density-dependence (Levitan et al. 1992), in which subsequent sea palm recruitment is reduced in the immediate area, especially where patches are discrete and small. Clear-cutting in zones, or selective-cutting, may increase harvest efficiency without the negative impact of extensive clear-cutting, but determining the size and number of these zones on a site-specific basis and subsequently enforcing such a system would be impractical. Alternatively, the blade cut-only harvest method could be fairly easily enforced, since possession of any part of the stipe or branches would constitute an infraction. Each kelp harvester's regulation packet could include a copy of the regulation and a diagram depicting the cutting method. In central and northern California a high percentage of sea palm beds occur within the boundaries of coastal state park lands. While the California Fish and Game Commission has the authority to regulate commercial kelp harvest, the California Department of Parks and Recreation (DPR) has the legal authority to control access across state park property to sea palm beds along state park shores, by virtue of a HARVEST EFFECTS ON SEA PALM GROWTH 67 California Code of Regulations section empowering DPR to limit commercial operations on park property, thus providing a measure of de facto protection to these beds (Dave Bartlett, DPR, pers. comm.). Since access from the sea is not controllable by DPR, it would still be legal under certain circumstances to harvest sea palm along park shores from a vessel. A comprehensive management scheme for sea palm might include prohibiting commercial and sport take in tidal areas along coastal state parks, while allowing commercial harvest elsewhere under the previously described scenario, and further, opening a limitedsport fishery for sea palm requiring the use of the blade cut method and a daily bag limit (by wet weight of blades). In order to ensure that some spore release occurs in a given area, commercial and sport harvest might be prohibited prior to July 1 . Also, the problem of one or more harvesters over-cutting an area or returning to previously cut plants too soon could be addressed by a commercial bag limit. ACKNOWLEDGMENTS The author would like to thank Ian Taniguchi and Don Hicks for their assistance on this project, as well as Frank Henry, Dave Parker and Joe Weinstein of the Department, and an anonymous reviewer, for their review and comments on the manuscript. LITERATURE CITED Abbott, I. A., and G.J. Hollenberg. 1976. Marine Algae of California. Stanford Univ. Press. 827p. Dayton, P.K. 1973. Dispersion, dispersal, and persistence of the annual intertidal alga, Postelsia palmaeformis Ruprecht. Ecology 54(2):433-438. Lawrence, J.M., and J.B. McClintock. 1988. Allocation of organic material and energy to the holdfast, stipe, and fronds in Postelsia palmaeformis (Phaeophyta: Laminariales) on the Califomia coast. Marine Biology 99:151-155. Levitan, D.R., M. A. Sewell, and F. Chia. 1992. How distribution and abundance influence fertilization success in the sea urchin Strongylocentrotus franciscaiuts. Ecology 73(1): 248-254. Nicholson, N.L. 1970. Field studies on the giant kelp Nereocystis. J. Phyc. 6:177-182. Nie, N.H., C.H. Hull, J.G. Jenkins, K. Steinbrenner, and D.H. Bent. 1975. Statistical Package for the Social Sciences. McGraw-Hill, New York. 675 p. Paine, R.T. 1988. Habitat suitability and local population persistence of the sea palm Postelsia palmaeformis. Ecology 69(6): 1787- 1794. Schmitz, K., and C.S. Lobban. 1 976. A survey of translocation in Laminariales (Phaeophyceae). Marine Biology 36:207-216. Received: 6 October 1993 Accepted: 17 January 1994 CALIFORNIA FISH AND GAME Calif. Fish a.id Game (80)2:68-79 1 994 DUCK AND SHOREBIRD REPRODUCTION IN THE GRASSLANDS OF CENTRAL CALIFORNIA ROGER L. HOTHEM and DANIEL WELSH' National Biological Survey Patuxent Environmental Science Center Pacific Research Group c/o Department of Wildlife and Fisheries Biology University of California Davis, CA 95616-5224 We studied the effects of contaminants in agricultural drainwater on the reproductive success of ducks and shorebirds nesting in the Grasslands of western Merced County, California during 1986 and 1987 and at the Mendota Wildlife Area in Fresno County in 1987. Nesting success and egg hatchability varied by species, site, and year, but were. In most cases, higher in the Grasslands than at Mendota. The primary cause of nest failure for ducks and shorebirds at both study sites was predation. Although concentrations of selenium (Se) were found to be elevated in certain Grasslands drainages, embryotoxic effects attributable to environmental contaminants were not observed for any species at either study site. INTRODUCTION Wetlands of the Grasslands in Merced County. California (Fig. 1 ). comprise the largest remaining tract of waterfowl habitat in California's San Joaquin Valley (Gilmer(^/a/. 1982). Between 1954 and 1985. managed marsh areas in the Grasslands were flooded in the autumn (September 1 5-November 1 ) using a mixture of agricultural drainwater and fresh irrigation water; after November 1. drainwater was used exclusively each year to keep marsh areas filled for duck hunting and other purposes (Grassland Water District and Grassland Water Task Force 1 986). In 1 984, this water contained an average of 50// g/L dissolved Se (Presser and Barnes 1985). or about 50 times the concentration in water at a nearby reference site, the Volta Wildlife Area (Saiki and Lowe 1987). In 1983. the mean concentration of Se in water samples from agricultural drainwater evaporation ponds at the Kesterson National Wildlife Refuge was 1 22// g/ L (Saiki and Lowe 1987). During 1983-1985, avian reproduction at the Kesterson ponds was impaired (including embryonic deaths and deformities) by elevated concentrations of dietary Se(Ohlendorf95^/c ) (J. P. Skorupa. U.S. Fish and Wildlife Serv ice. pers.comm.). Therefore, our assumption that late-stage collected eggs would have been successful imparts minimal bias to our hatchabi I ity estimates. We used two- tailed standard-normal tests (r-tests) for between-year and between-location comparisons of nesting success and cause-specific nesting fai lure rates. These tests are discussed by Hensler and Nichols { 1981 ) and Bart and Robson ( 19S2) in relation to statistical comparisons of estimated nesting success by the Mayfield ( 1961 ) method. The probability level for comparisons of nesting success rates was P < 0.03. We compared cause-specific failure rates by multiple statistical treatments of the same data. To assess hatchability, we calculated the ratio of hatched eggs to adjusted clutch size for each successful nesting attempt. Following arcsine transformation, we compared hatchability data with two-factor analysis of variance, and. if necessary, Tukey mean separation tests. We calculated adjusted clutch si/es by subtracting from full clutch sizes all randomly collected eggs and eggs that disappeared from nests prior to predicted hatching dates. We rejected two types of eggs from the analyses of hatchability those with embryos younger than about 13 days which could not be accurately assessed for normality, and those older than 13 days v\ith uncertain viability. RESULTS Nest Abundance We found 1 26 duck and 83 shorebird nests in the Grasslands in 1 986 and 1 43 duck and 89 shorebird nests in 1 987. We found 46 shorebird nests, and the CW A found 2 1 0 duck nests at Mendota in 1987 (Table I ). We searched the same areas both years and found that the species composition of nesting ducks was different in 1987. The percentage of the total nests that were cinnamon teal {Anas cyaiioptera), for example, declined from about ■MW( in 1986 to 13% in 1987. The percentage that were mallard {A. phuyihyiu lios) nests, however, increased from 17% in 1986 to 31% in 1987, while the percentage of gadwall (A. strepera) nests increased from 33% in 1 986 to 54% in 1 987. At Mendota. mal lard nests (42%) comprised slightly more of the total than did gadwall nests (35%). Fewer black-necked stilt (Hinianfopiis mexicanus) nests were found in the Grasslands in 1987 than in 1986. but numbers of American avocet (Rccnrvirosfia anwricana) nests were about the same each year. About twice as many killdeer (Chantdriiis vocifcrns) nests were found in the Grasslands in 1987 as in 1986. At Mendota, stilts ( 19 nests) and avocets (8 nests) nested only during the short time that a few ponds were flooded. Nineteen killdeer nests were found along Mendota access roads and levees. AVIAN REPRODUCTION IN THE GRASSLANDS 73 Tabic I. Falcs ol' nests and percent nesting success (95'/^ CI) of aquatic birds in the South Grasslands (SG) and at the Mendola Wildlile Area (MWA), California. 1986-1987. Number of nests Exposure Percent nesting Species' Term, by Year-site FcHind incr . HiUchedL obsrvr. Jailed _jlays success 95% CI Mallard 1986-SG 21 18 7 0 1 1 239.0 19.2 7.2-50.3 1987-SG 45 40 16 I 23 443.5 15.5 7.2-32.9 1987-MWA 87 83 40 1 42 1184.0 28.2 1 9.2-4 1.3 Gad wall 1986-SG 42 42 28 1 13 528.5 41.8^== 26.0-67.0 1987-SG 77 75 29 0 46 942.5 17.4 10.4-28.7 1987-MWA 74 70 29 0 41 975.5 -)i 2 14.0-35.1 Northern Pintail 1986-SG 8 8 3 0 5 69.5 9.2 1.1-69.8 1987-SG 2 2 2 0 0 27.0 100 1987-MWA 14 12 1 1 10 117.0 5.7 0.9-3.2 Cinnamon Teal 1986-SG 5\ 45 26 0 19 652.5 36.6* 23.2-57.4 1987-SG 18 16 2 1 13 222.0 12.9 4.1-38.5 1987-MWA 34 31 12 1 18 35 1 .0 16.7 7.2-37.8 Killdeer 1986-SG 20 20 11 0 9 233.5 32.0 15.0-66.7 1987-SG 42 42 24 0 18 583.0 40.3 26.4-61.1 1987-MWA 19 7 T 0 5 78.5 14.8 2.6-75.4 Black-necked Still 1986-SG 28 28 7 0 21 221.0 8.2 2.8-23.5 1987-SG 10 10 1 0 9 49.5 0.6 0-14.5 1987-MWA 19 15 7 0 8 157.5 272=;-:= 10.8-66.0 American Avocet 1986-SG 35 35 12 0 23 379.0 19.6- 10.0-37.9 1987-SG 37 33 4 0 29 256.5 4.4 1.4-13.4 _. J987-MWA 8 __]__ 3 0 4 71.5 22.4 _4,9-93,l "Too few northern shoveier nests found to be included in analyses (4 nests SG-1 986; 1 nest SG- 1987; 1 nest MWA). "Nests already terminated when found, nests destroyed or abandoned due to searching efforts, and nests of unknown fate were excluded from analyses. * Within species, success rate significantly higher in 1986 than in 1987 in SG (P< 0.05). *' Within species success rate significantly higher at MWA than in SG in 1987 (P< 0.05). Nesting Success Predation was the primary cause of nest failure both in the Grasslands and at Mendota. With the exception of pintails, at least 5(V/( of the duck nests monitored in this study were destroyed by predators. A second major cause of nesting failure, observed only at Mendota. was embryo death. All embryos were found dead in some 74 CALIFORNIA FISH AND GAME Tnblc 2. Cause-specific failure rates (percentages and 957( CI) of duck nesting from the South Grasslands (SG) and the Mendota Wildhfc Area (MWA). California. I9S6-19X7.' Species Year-Site Embryo (^No. nests) Predation Pesemon_ Flooding Cattle deuth Mallard |yX6-SG 73.4 7.3 0 0 0 (IK) (51.6-95.3) (0-21.2) 1987-SG 73.5 7.3 0 3.7 0 (40) (58.0-89.0) (0-17.1) (0-10.7) iyS7-MWA .54.7 0 1.7 0 10.3 * (S3) (42.3-67.0) (0-5.0) (2.5-18.0) Gadwall 1986-SG 53.7 4.5 0 0 0 (42) (33.6-73,8) (0-13.0) 1987-SG 77.3 3.6 0 1.8 0 (75) (67.1-87.4) (0-8.5) (0-5.3) 1987-MWA 62.6 3.8 1.9 0 7.6 * (70) (50.1-75.1) (0-8.9) (0-5.6) (0.4-14.7) Nortiiern Pintail" 1986-SG 36.3 0 18.2 36.3 0 (8) (0-76.1) (0-50.2) (0-76.1) 1987-MWA 75.4 0 0 0 18.8 (12) (50.7- !()()) (0-42.3) Cinnamon Teal 1986-SG 50.0 3.3 0 10.0 0 (45) (32.6-67.5) (0-9.8) (0-20.7) 1987-SG 73.7 0 6.7 6.7 0 (16) (52.8-94.7) (0-19.4) (0-19.4) 1987-MWA 69.4 4.6 4.6 0 4.6 (31) (51.0-87.8) (0-13.5) (0-13.5) (0-13.5) ^Vehicles and unknown were other infrequent causes of nesting failure. "Only 2 nests found in the South Grasslands in 1987. * Failure rates at MVJA and SG in 1 987 differed (P < 0.01 ). active mallard. iu)i"thcrii pintail (/\. acuta), gadwall. and cinnamon leal nests, and the failure rate due lo embryo death was higher at Mendota than in the Grasslands for both mallards {P = ().()()5) and gadwails (P = 0.019) (Table 2). Other causes of nesting failure that were important for some species of ducks in one or more years were desertion, flooding, and trampling by cattle. Predation was also the leading cause of failure of shorebird nests. In the South Grasslands more (P = 0.005) stilt nests were lost to predation in 1987(99.3'/^ ) than in 1986 (78.77f ). In 1987, fewer still nests were destroyed by predators at Mendota (6.3.7'7r ) than in the Grasslands {99.y/f). but more killdeer nests were destroyed at Mendota (85. 2Vf ) than in the Grasslands (46.5^/r ). Predation on avocet nests was high AVIAN REPRODUCTION IN THE GRASSLANDS 75 Table 3. Egg hatchability in successful nests in the South Grasslands (SG) and at Mendota Wildlife Area (MWA), California, 1986-1987. Species Year-Site Nests Mallard 1986-SG 7 1987-SG 16 1987-MWA 39" Gadwall 1986-SG 28 1987-SG 29 1987-MWA 29 Northern Pintail 1986-SG 3 1987-SG 2 1987-MWA 1 Cinnamon Teal 1986-SG 26 1987-SG 2 1987-MWA 12 Hatchabil ity X SE 94.6 5.4 96.1* 3.2 79.9 4.6 93.3** 2.2 77.5* 5.1 63.7 4.8 89.7 5.2 83.3 6.7 75.0 96.7 1.8 83.3 16.7 75.1 8.6 ^Even though 40 nests were successful, n = 39 because total eggs that hatched in one nest was unknown, and hatchability could not be calculated. * Hatchability higher (P < 0.05) than at MWA. " Hatchability in SG higher (P< 0.05) in 1986 than in 1987. in the Grasslands in both 1986 (80.3%) and 1987 (85.7%) and at Mendota (77.6%). A second major source of mortality for killdeer was motor vehicle traffic, because most nesting occurred along roads where nests were especially vulnerable to destruction by vehicles. In the Grasslands, the nesting success of gadwalls, cinnamon teals, and avocets waslower(/'<0.05)in 1987 than in 1986(Table 1 ). The only species which had poorer (P < 0.05) nesting success in the Grasslands than at Mendota in 1987 was the black- necked stilt. Too few northern pintail and northern shoveler (A. clypeata) nests were found to allow statistical comparisons. Hatching Success We found no abnonnalities in any late-stage embryos from 79 duck and 32 shorebird eggs collected from monitored nests in the Grasslands in 1 986, from 93 duck and 29 shorebird eggs from nests in the Grasslands in 1987, and from 29 duck and 21 shorebird eggs from nests at Mendota in 1987. In the Grasslands, hatchability of gadwalls, but not mallards or killdeer, was lower {P = 0.012) in 1987 than in 1986 (Table 3). Comparisons were not made for other species because too few nesting attempts were successful in one or both years. In 1 987. 76 CALIFORNIA FISH AND GAME hatchability was higher in the Grasslands than at Mendota for mallards (P = 0.003 ) and gadwalls (P = 0.004). the only species with sufficient sample sizes for statistical comparisons (Table 3). DISCUSSION In this study, we found that, overall, the most common species of duck nesting in the Grasslands was the gadwall, followed by cinnamon teals and mallards. Mallard, followed by gadwall nests, were most abundant at Mendota in 1987. As in previous studies (Anderson 1956, Gray and Schultze 1977), nests of northern shovelers and northern pintails were rarely found (<3% of all nests). The greatest observed change in species composition was the decrease in the relative numbers of cinnamon teal nests. Drier conditions during 1987 than during 1 986 may have reduced the quality of nesting cover, thus contributing to the observed differences in species compositions between years. In addition, during 1 987, ranchers put cattle on the waterfowl hunting clubs earlier than in 1986, and grazing and trampling seemed to reduce the amount and quality of saltgrass {Distichlis spp.), a preferred habitat for nesting cinnamon teals. As in previous studies in the Grasslands (Anderson 1956, Gray and Schultze 1977), predation was the major cause of nesting failure for ducks. In this study, predation rates in the Grasslands were about 75% for mallards both years and for gadwalls in 1987. The increased predation rates (about 50% higher) for gadwalls and cinnamon teals in 1987 may have been related to poorer habitat quality that year. Predation rates on stilt and avocet nests in the South Grasslands were high both years of this study, but they were especially high for stilts in 1 987. Stilts nested almost exclusively on duck-blind islands, and dry conditions in 1987 exposed gravel walkways to these islands earlier in the nesting season than in 1 986. Tracks indicated that mammalian predators, primarily coyotes (Canis lafrans), used these walkways to reach the nests. Despite the presence of elevated concentrations of Se in eggs from certain drainages in the Grasslands (Hothem and Welsh 1994), defomiities and other toxic effects were not seen in avian embryos during either year of our study. Most mean Se concentrations in eggs from the Grasslands were above levels observed at reference sites but below the 1 3-24;/g/g threshold for teratogenesis suggested by Skorupa and Ohiendorf ( 1991 ). However, the presence of elevated concentrations of Se in eggs (Hothem and Welsh 1994) and adult birds (PavegVio et ci I. 1992) suggests that certain areas in the Grasslands were still contaminated with Se during 1 986 and 1 987, despite the change to uncontarninated water for irrigation and autumn flooding in 1985 (Grassland Water District and Grassland Water Task Force 1986). Previously reported rates of nesting success of ducks in the Grasslands ranged from 9.4% (Anderson 1956) to 20% (Gray and Schultze 1977). Nesting success in our study was within this range or slightly higher. However, because traditional methods render higher estimates of nesting success than the Mayfield method (Mayfield 1 96 1 , Johnson 1979). our estimates were more conservative than the estimates from previous studies. AVIAN REPRODUCTION IN THE GRASSLANDS 77 In 1986, hatchability of duck eggs in the Grasslands (Table 3) was similar to, or better than, the rates in previous studies of waterfowl in California (Anderson 1956, 1957, 1960; Hunt and Naylor 1955; Miller and Collins 1954). Mean hatchability at Mendota, however, did not exceed 80% for any duck species, which was lower than has been reported for most studies of nesting ducks in California. Of 746 monitored duck nests during previous studies in the Grasslands, only one clutch contained all eggs with dead embryos (Anderson 1956). None of the clutches in the Grasslands during our study had 100% dead embryos, but four species of ducks at Mendota had from 4.6 to 18.8% of their clutches in this category. Causes for this reduced hatchability at Mendota are not known, but chemical analyses of eggs indicated that mortality was not related to contamination by arsenic, boron, or selenium (Hothem and Welsh 1994). Further study of waterfowl nesting at Mendota is needed to determine the cause of this mortality. Our results suggest that relatively high rates of nesting success and egg hatchability may be found even when concentrations of Se are on the lower end of the range believed to cause harm. Fledging success, however, may be affected, and it should be evaluated in future studies of areas with medium to low concentrations of Se. ACKNOWLEDGMENTS We thank G.R. Zahm, F.L. Paveglio, and R. Huddleston for assisting with access to study areas and for logistical support. K.L. Blakely, S.J. Clark, C.R. Hothem, CD. Johnson, D.P. Kemner, and J. Mackay assisted in the field. B. Duggers and his California Waterfowl Association crew provided waterfowl data from the Mendota Wildlife Area, and M.R. McLandress and A.E.H. Perkins helped interpret those data. K.C. Marois provided laboratory assistance, and CM. Bunck provided statistical assistance. We thank the Grassland Water District Manager and board members for their cooperation and the owners and managers of the duck clubs for granting access to study sites. H.M. Ohlendorf assisted with planning and reviewed the manuscript. P.H. Albers, G.H. Heinz, F.L. Paveglio, J.P. Skorupa, and T.R. Stanley, Jr. also reviewed the manuscript. This study was funded under the U.S. Bureau of Reclamation/ U.S. Fish and Wildlife Service Intra-agency Agreement No. 6-AA-20-04170. LITERATURE CITED Anderson, W. 1 956. A waterfowl nesting study on the Grasslands, Merced County, California. Calif. Fish Game 42:117-130. . 1957. A waterfowl nesting study in the Sacramento Valley, California, 1955. Calif. Fish Game 43:71-90. 1 960. A study of waterfowl nesting in the Suisun marshes. Calif. Fish Game 46: 1 1 7- 1 30. Bart, J., and D. S. Robson. 1982. Estimating survivorship when the subjects are visited periodically. Ecology 63:1078-1090. Gilmer, D. S., M. R. Miller, R. D. Bauer, and J. R. LeDonne. 1 982. California's Central Valley wintering waterfowl: concerns and challenges. Trans. N. Am. Wildl. Nat. Resour. Conf. 47:441-451. 78 CALIFORNIA FISH AND GAME Grassland Water District, and Grassland Water Task Force. 1986. Ecological and water management characterization of Grassland Water District. Los Banos, Calif. 62 p. Gray, R. L., and R. F. Schultze. 1 977. Nesting on water bank lands in Merced County. Cal-Neva Wildl. Trans. 97-102. Heisey. D. M..andT. K. Fuller. 1985. Evaluation of survival and cause-specific mortality rates using telemetry data. J. Wildl. Manage. 49:668-674. Hensler, G. L.. and J. D. Nichols. 1981. The Mayfield method of estimating nesting success: A model, estimators, and simulation results. Wilson Bull. 93:42-53. Higgins, K. F., L. M. Kirsch. and I. J. Ball. Jr. 1969. A cable-chain device for locating duck nests. J. Wildl. Manage. 33: 1009- 10 11 . Hothem, R. L..and D. Welsh. 1994. Contaminants in eggs of aquatic birds from the Grasslands of Central California. Arch. Environ. Contam. Toxicol. 27:180-185. Hunt. E. G.. and A. E. Naylor. 1 955. Nesting studies of ducks and coots in Honey Lake Valley. Calif. Fish Game 41:295-314. Johnson, D. H. 1979. Estimating nest success: The Mayfield method and an alternative. Auk 96:651-661. Klett, A. T., H. F. Duebbert, C. A. Faanes, and K. F. Higgins. 1986. Techniques for studying nest success of ducks in upland habitats in the prairie pothole region. U.S. Fish Wildl. Serv., Resour. Publ. 158. 24 p. Mayfield, H. F. 1961. Nesting success calculated from exposure. Wilson Bull. 73:255-261. . 1975. Suggestions for calculating nest success. Wilson Bull. 87:456-466. Miller. A. W.. and B. D. Collins. 1954. A nesting study of ducks and coots on Tule Lake and Lower Klamath National Wildlife Refuges. Calif. Fish Game 40:17-37. Ohlendorf, H. M. 1989. Bioaccumulation and effects of selenium in wildlife. Pages 133-177 //; L.W. Jacobs, ed. Selenium in Agriculture and the Environment. SSSA Spec. Publ. No. 23. American Society of Agronomy and Soil Science of America. Madison, Wis. . D. J. Hoffman, M. K. Saiki, and T. W. Aldrich. 1986rt. Embryonic mortality and abnormalities of aquatic birds: Apparent impacts of selenium from irrigation drainwater. Sci. Total Environ. 52:49-63. . R. L. Hothem. T. W. Aldrich, and A. J. Krynitsky. 1987. Selenium contamination of the Grasslands, a major California waterfowl area. Sci. Total Environ. 66: 169-183. , , C. M. Bunck. T. W. Aldrich. and J. F. Moore. 1 986/?. Relationships between selenium concentrations and avian reproduction. Trans. N. Am. Wildl. Nat. Resour. Conf. 51:330-342. . , and D. Welsh. 1989. Nest success, cause-specific nest failure, and hatchability of aquatic birds at selenium-contaminated Kesterson Reservoir and a reference site. Condor 91:787-796. Paveglio. F. L.. C. M. Bunck. and G. H. Heinz. 1 992. Selenium and boron in aquatic birds from Central California. J. Wildl. Manage. 56:31-42. Presser. T. S.. and 1. Barnes. 1985. Dissolved constituents including selenium in waters in the vicinity of the Kesterson National Wildlife Refuge and the West Grasslands, Fresno and Merced Counties, California. Water Resources Invest. Rep. No. 85-4220, U.S. Geol. Surv., Menlo Park, Calif. 73 p. Saiki, M. K., andT. P. Lowe. 1987. Selenium in aquatic organisms from subsurface agricultural drainage water, San Joaquin Valley, California. Arch. Environ. Contam. Toxicol. 16:657- 670. Shelton, L. R., and L. K. Miller. 1988. Water-quality data. San Joaquin Valley, California, March 1985 to March 1987. U.S. Geol. Surv. Open-file Rep. No. 88-479. 210 p. AVIAN REPRODUCTION IN THE GRASSLANDS 79 Skorupa, J. P., and H. M. Ohiendorf. 1991. Contaminants in drainage water and avian risk thresholds. Pages 345-368 /// A. Dinar, and D. Zilberman, eds. The economics and management of water and drainage in agriculture. Kluwer Academic Publ.. Boston. Mass. Weller. M. W. 1 956. A simple field candler for waterfowl eggs. J. Wildl. Manage. 20: 1 1 1 - 1 1 3. Westerskov. K. 1950. Methods for determining the age of game bird eggs. J. Wildl. Manage. 14:56-67. Received: 16 October 1993 Accepted: 16 August 1994 CALIFORNIA FISH AND GAME Calif. Fish and Game (80)2:80-83 1 994 ROOSEVELT ELK DIETARY QUALITY IN NORTHERN COASTAL CALIFORNIA PETER J. P. GOGAN' California Department of Parks and Recreation Nortfiern Region Headquarters 396 Tesconi Court Santa Rosa, California 95401-4653 and REGINALD H. BARRETT Department of Environmental Science, Policy, and Management 145Mulford Hall University of California Berkeley, California 94720 We investigated crude protein (CP) levels in two herds of Roosevelt elk {Cervus elaphus rooseveiti) at Prairie Creek Redwoods State Park (PCRSP), Humboldt Co., California, during 1 987 in response to concerns that the elk were nutritionally stressed. Both herds showed the same annual pattern of fecal CP levels with highest values in the spring months and lowest values in the fall months. Crude protein levels indicate that neither herd was nutritionally stressed relative to protein nutrition. INTRODUCTION Roosevelt elk {Cervus elaphus rooseveiti) have occupied the area currently within the boundaries of Prairie Creek Redwoods State Park (PCRSP), Humboldt Co.. California, continuously since at least 1937 (Harper etal. 1967). Distinct herds of elk have been recognized occupying the Boyes Prairie and Gold Bluffs Beach sections of the park (Franklin and Lieb 1979). Elk within the park are not harvested or manipulated in any way although in the past they have been u.sed as a source for translocations elsewhere in northern California (Harper et al. 1967. D. A. Jessup, California Department of Fish & Game, pers. commun.). Establishment of Redwood National Park immediately adjacent to PCRSP in 1968 further buffered elk from direct manipulation. California Department of Parks and Recreation personnel became concerned that poor body conformation and low cowicalf ratios (Mandel and Kitchen 1979) were indicative of nutritional stress. We opted to use crude protein (CP) levels in fecal samples as a rapid, nonintrusive means of assessing annual dietary quality of elk. Protein is essential for body maintenance and growth, reproduction, and lactation (Nelson and Leege 1982). Dietary CP levels reflect other indices of dietary quality such as in vitro dry matter digestibility and levels of dietary phosphorous (Leslie and Starkey 1984, 1987, Kie 1988). 'Current address: Greater Yellowstone Field Station, National Biological Survey, P.O. Box 168, Yellowstone National Park, Wyoming 82190 80 ROOSEVELT ELK DIET QUALITY 81 STUDY AREA Prairie Creek Redwoods State Park lies along the northern Cahfomia coastline approximately 75 km north of Eureka. Vegetation of the PCRSP is classified as grand fir-sitka spruce forest (Kuchler 1977). Elk herds using the Gold Bluffs Beach and Boyes Prairie portions of the park occupy distinct, nonoverlapping ranges (Franklin and Lieb 1979). The Gold Bluffs Beach herd increased from 15 animals in 1965 (Franklin and Lieb 1979) to 50 by 1979 (Mandel and Kitchen 1979) while the Boyes Prairie herd increased from 25 to 70 over the same time period (Franklin and Lieb 1979, Mandel and Kitchen 1979). METHODS About 20 elk fecal pellets were collected from each of five different fresh defecations at each of the two sample areas on a monthly basis from January 1987 through January 1988. Fresh samples were placed in plastic bags and frozen for up to six months until analyzed. Samples from each area were pooled by month through June 1987 for Gold Bluffs Beach and through July 1987 for Prairie Creek but were analyzed individually for both sites thereafter. Fecal nitrogen (FN) content was determined by the Kjeldahl method (Williams 1984). Crude protein was determined by multiplying the percent FN content by 6.25 (Nelson and Leege 1982). Ninety-five percent confidence limits were calculated for the mean of all estimates produced by analyzing individual samples. RESULTS The percent CP in both herds showed the same annual pattern with relatively high values (> 19%) in the spring months and relatively low values (< 1 5%) during the fall months (Fig. 1 ). The highest (20%) and lowest (9% ) values were recorded for the Gold Bluffs Beach herd in April and November, respectively. At no time did the CP level drop to 4 to 7% or less. The only significant difference in fecal CP between herds occurred in November 1 987, when the Gold Bluff value was 9% and the Boyes Prairie value was 14%. DISCUSSION Fecal CP levels in free-ranging elk reflect changes in forage quality (Leslie et al. 1984), and analysis of fecal CP is an appropriate tool for comparisons of seasonal forage quality between herds utilizing similar habitat types (Leslie and Starkey 1 987 ). Fecal CP levels can be a misleading indicator of dietary quality when values are elevated by high levels of tannins in ingested plants, primarily forbs and shrubs (Hobbs 1 987). This concern may be allayed in the case of Roosevelt elk at PCRSP as their diet consists of 58-76% grasses throughout the year (Harper et al. 1967). Differences in estimates of fecal CP levels from individual or composite samples have 82 CALIFORNIA FISH AND GAME been found to be minimal (Jenks et al. 1989). The annual pattern of fecal CP levels for both Roosevelt elk herds at PCRSP is comparable to levels for tule elk at Point Reyes National Seashore ( PRNS ), Marin Co., with spring season peaks of approximately 1 9% and fall lows of approximately 13% (Gogan and Barrett, unpubl. data). This was achieved on diets of primarily grasses and forbs at both locales (Harper et al. 1967, Gogan 1986). The seasonal CP levels for both elk subspecies in the Mediterranean- like climate of northern coastal California contrast with those for Roosevelt elk in the temperate climate-influenced Olympic National Park (ONP), Washington, where seasonal CP levels drop to as low as 8% in winter and peak at 20% in summer (Leslie and Starkey l985:Table 1 ). There, the elk diet consists predominantly of trees and ferns in winter and forbs, grasses, and ferns in summer (Leslie et al. 1984). Crude protein levels for fecal samples from Roosevelt elk at PCRSP reveal no differences in seasonal patterns between elk herds at Gold Bluffs Beach or Prairie Creek, except that the fecal CP level was significantly greater for the Boyes Prairie herd in November, 1 987. Neither herd was nutritionally stressed relative to protein nutrition. 22 ^20h ■| 18 o Q.16 CD ■D ^. O "c5 o CD LL 14 12 10 8 Gold Bluff Herd Boyes Prairie Herd ^ tn cc cr >: -z. 00 111 < Q. < 3 ^ Li- 3 < ^ ^ -I O CL I- 3 3 m o ^ < CO o > o s O LJJ 2? Figure 1 . Monthly fecal crude protein (CP) values (6.25 x ppm fecal nitrogen) from two herds of Roosevelt elk at Prairie Creek Redwoods State Park, California. Month (1) is January 1987 and month (13) is January 1988. Vertical lines on some values indicate 95% confidence limits (n = 5). The overall mean monthly CP value is indicated by the trend line. ROOSEVELT ELK DIET QUALITY 83 Indeed, lower CP levels have been recorded for tule elk at PRNS (Gogan and Barrett, unpubi. data) and Roosevelt elk at ONP (Leslie et al. 1984). The extent to which elk at PCRSP may be limited by other nutrient requirements remains unknown. LITERATURE CITED Franklin, W. L., and J. W. Lieb. 1979. The social organization of a sedentary population of North American elk: a model for understanding other populations. Pages 185-195/// M. S. Boyce and L. D. Hayden-Wing, eds. North American elk: ecology, behavior and management. University of Wyoming Press, Laramie. WY. 294 p. Gogan, P. J. P. 1986. Ecology of the tule elk range. Point Reyes National Seashore. Ph.D. Dissertation, University of California, Berkeley. 441 p. Harper, J. A., J. H. Harn, W. C. Bently, and C. F. Yocom. 1967. The status and ecology of the Roosevelt elk in California. Wildlife Monograph 16: 1-49. Hobbs, N. T. 1987. Fecal indices to dietary quality: a critique. J. Wildl. Manage. 51(2): 317- 320. Jenks. J. A., D. M. Leslie. R. L. Lochmiller. M. A. Melchoirs, and W. D. Warde. 1989. Effect of compositing samples on analysis of fecal nitrogen. J. Wildl. Manage. 53( I ): 2 1 3-2 1 5. Kie, J. G. 1988. Performance in wild ungulates: measuring population density and conditions of individuals. USDA Forest Service, Gen. Tech. Report PSW-106. 17 p. Kuchler, A. W. 1977. The map of the natural vegetation of California. Pages 909-938 in M. G. Barbour and J. Major, eds. Terrestrial vegetation of California. John Wiley and Sons, Inc., New York, NY. 1002 p. Leslie, D. M., and E. E. Starkey . 1 985. Fecal indices to dietary quality of cervids in old-growth forests. J. Wildl. Manage. 49( 1 ): 142-146. , and . 1987. Fecal indices to dietary quality: a reply. J. Wildl. Manage. 51(2): 321-325. _, and M. Vavra. 1984. Elk and deer diets in old-growth forests in western Washington. J. Wildl. Manage. 48(3): 762-775. Mandel, R. D., and D. W. Kitchen. 1 979. The ecology of Roosevelt elk in and around Redwood National Park. Unpubi. report. Dept. of Wildlife Management, Humboldt State University, Areata, CA. 69 p. Nelson, J. R., andT. A. Leege. 1982. Nutritional requirements and food habits. Pages 323-367 /// J. W. Thomas and D. E. Toweill, eds. Elk of North America, ecology and management. Stackpole Books, Harrisburg, PA. 698 p. Williams, S., ed. 1984. Official methods of analysis of the Association of Official Analytical Chemists. Fourteenth ed. Association of Official Analytical Chemists, Washington, D.C. 1141 p. Received: 5 August 1993 Accepted: 20 April 1994 CALIFORNIA FISH AND GAME Calif. Fish and Game (80)2:84-87 1 994 A PORTABLE FIELD SAMPLING TABLE FOR DOCK-SIDE SAMPLING OF FISH ROBERT R. LEOS California Department of Fish and Game Marine Resources Division 20 Lower Ragsdale Drive, Suite 100 Monterey, CA 93940 In 1977, the California Department of Fish and Game and the National Marine Fisheries Service initiated a joint fisheries monitoring program known as the Cooperative Rockfish Survey. The program involves gathering biological data from commercial fishery landings at unloading sites in ports along the California coast. Data collected consist of species length, sex, and female gonadal condition. Otoliths are removed for age determination analysis. To accomplish these tasks, the field sampler needs a suitable place to set up sampling equipment consisting of a measuring sheet holder, plastic measuring sheets, otolith trays, knives, scalpels, forceps, plastic bins, and clean up gear. A portable sampling table with wide applicability to field use, meeting the field samplers needs, is discussed. This portable sampling table is not limited to dock-side sampling offish, but is adaptable to many situations where a field sampling table is needed. The sampling table may be used on small research boats, rocky shore and beach sites, river banks, skiff launch areas, wharfs, jettys, and piers. It also can be used as a work station for sampling other species such as birds, small animals, and plants. It is ideally suited for on-the-spot examination, measuring, and dissection of most small specimens. The sampling table was designed with the following criteria in mind: 1 ) it should be easy to carry to and from sampling sites, 2) quickly and easily set up out of the way of the receiver's operations while still allowing the sampler to view and monitor unloading, 3) it should be stable and self-contained, 4) simple and easy to clean, and 5) easily disassembled and packed up for transport. The .sampling table consists of a "brief case" style box that measures 3 1 -inches x 3'/2-inches x 15'/2-inches (Fig. 1). With the exception of the top, all wooden parts of the sampling table are made of Douglas fir. The four sides and bottom are made of '/:- inch thick boards. I used boards instead of plywood because I prefer the workability of boards to plywood. The front and right sides (as viewed from the front) are hinged to swing down and out of the way. The top cover is made of Masonite board, '4 -inch X 30'4-inches x 14%-inches, and slides into '^-inch-wide grooves, cut Ya inch down from the top edge of the left, back, and right sides. A )<4-inch-diameter hole drilled near the front of the top cover facilitates its removal. The bottom boards are butt jointed together. Attached to the top surface are two wooden rails made of '/4-inch x )^-inch X 30-inch wooden slats (Fig. 2). A routed-out. 1/16-inch x 1/16-inch area the length of each slat forms a lip along one edge of each slat. These face each other creating a holding channel to slide plastic measuring sheets into. A sampling table of this size 84 NOTES 85 f^ ^ ^w^ 1 ^ %" grooves 0 =^ window bolt hinged right side draw catch sliding top cover carrying handle hinged front side Figure 1 . Sampling table in the closed, "brief case" position (insert), and shown partially open. accommodates plastic measuring sheets approximately 30 inches in length. The distance between the slats is set depending upon the width ofthe measuring sheets. The slat edges opposite from the lips are bevel cut for appearance and ease of cleaning. Draw catches and hinges attached in appropriate positions allow the front and right sides to swing out ofthe way or to be locked into place as necessary (Fig. 2). The right side is also locked to the back side with a window bolt. Four 3/8-inch x 5/8-inch wooden slats attached along the edges of the underside of the box create a frame for the scissor-type legs to open up and wedge against. The leg base is made of two sets of 1 '/2-inch x yj-inch x 35-inch wooden slats (Fig. 2). Each set of legs is fastened together with a bolt, washer, and wing nut through a hole drilled approximately one- third the distance down from the top of the legs. Four 5/8-inch diameter wooden 86 CALIFORNIA FISH AND GAME y*. " groove window bolt draw catch leg base wooden rails groove wooden dowel Figure 2. Sampling table in the open position showing its position relative to the leg base. dowels connect the legs and serve as support cross pieces. Both ends of each leg are angle-cut so that the tops fit under the table and wedge into place, and the bottoms set flat on the ground when the legs are fully opened. Leg length may be varied, depending upon the height of the person using the table. Brass hardware and marine glue were used throughout the unit for assembly. The entire unit was painted with a heavy duty marine paint. The sampler sets up the unit by first opening the scissor leg base to the approximate width of the underside of the table and loosely locks the legs into position using the w ing nuts at the leg junctions. The table is placed on the leg base with the handle facing the sampler. The legs are then adjusted for a snug fit and locked into place using the wing nut arrangement. Unsnapping the draw catches on the left and right sides allows NOTES 87 the sampler to swing the front side down and out of the way. The top cover is slid out and placed out of the way, uncovering the sampMng equipment stored inside the unit. The sampler now can arrange this equipment to facilitate sampling. Additional plastic measuring sheets are kept inside the unit during storage. A new measuring sheet is installed by opening the right side, inserting the sheet, then closing and locking that side with the window bolt. With the right side and a new measuring sheet locked in place, the sampler has a convenient semi-enclosed table to measure and cut fish. The front side is usually left in the open position, hanging down and out of the way during sampling. Sampling tools are within easy reach and are less apt to be misplaced, dropped, or lost. When sampling is completed, the entire unit and sampling equipment are washed, brushed and allowed to drip dry for a few minutes. All the equipment is then placed inside the unit and the right side is closed and locked. The top cover is slid into place and the front side is closed and locked. The sampler then lifts the table off the scissor leg base, loosens the leg wing nuts, folds up the legs, and carries the unit away. The sampling table has been in use for about 2 years. Other than normal wear and tear only one minor problem occurred during that time. The Masonite top became frayed and soft at the corners. This problem could probably be avoided by using a thin sheet of marine plywood instead of Masonite. ACKNOWLEDGMENTS I thank Bob Lea of the Department of Fish and Game for the initial idea for the paper, and Jerry Spratt and Paul Wild of the Department of Fish and Game for their reviews, comments, and suggestions for the manuscript. I also thank Lara Ferry for drawing the preliminary illustrations. Received: 24 September 1992 Accepted: 4 August 1993 INSTRUCTIONS FOR CONTRIBUTORS EDITORIAL POLICY California Fish and Game is a technical, professional, and educational journal devoted to the conservation and understanding of fish, wildlife, and native communities. Original manuscripts submitted for consideration should deal with California flora or fauna, or provide information of direct interest and benefit to California researchers and managers. 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