Yellow Perch Recruitment Research Articles

Yellow Perch Research and Management in Lake Michigan

Yellow perch (Perca flavescens) is an important component of near-shore freshwater fish communities. It plays an important role in energy cycling and transfer, and is available to nearly all segments of the angling public and to commercial fisheries. Beginning around 1990, yellow perch population density declined in Lake Michigan due in part to an almost complete lack of recruitment. In response to this dramatic decline, the Lake Michigan Yellow Perch Task Group (YPTG) was formed (under the auspices of the Great Lakes Fishery Commission's Lake Michigan Committee) to develop a multi-agency research initiative to identify the likely cause(s) for yellow perch recruitment failure. The multi-agency effort has made substantial progress in addressing this question, and serves as a model for agencies to work collaboratively to address important management questions with a sound research strategy. We highlight the work conducted during 1997–2001 to address five factors (predation, zooplankton availability, temperature, mass water movement, spawning stock characteristics) potentially influencing recruitment of yellow perch. Thus far, work to address influence of forage availability and stock characteristics on yellow perch recruitment has yielded significant results. The YPTG continues work to quantify the relative importance of (and interaction among) the factors described above in determining yellow perch survival and recruitment. The cooperative approach used by the YPTG to address these issues holds great promise, and can be used by agencies managing shared resources regardless of the system in question.

Characterization of Growth and Winter Survival of Age-0 Yellow Perch in Southeastern Lake Michigan

Reduced growth and increased winter mortality are possible mechanisms for poor recruitment of age-0 yellow perch ( Perca flavescens) in southeastern Lake Michigan. To assess the role of growth variability on recruitment of age-0 yellow perch, we quantified length-by-date and abundance during 1996–2002. Analyses revealed significant differences in length among years and sites. To resolve spatial trends, we contrasted the 1998 cohort from southeastern Lake Michigan with conspecifics from populations located within and beyond the Lake Michigan watershed. These analyses identified significant differences in length; trends suggested that the capacity for growth in the cohort from southeastern Lake Michigan was similar to these other populations. To characterize winter survival for the 1998 age-0 cohort, otoliths from age-1 perch in 1999 were used to back-calculate length (BCL) from the previous autumn. The BCL distribution was significantly larger than the 1998 distribution, but analyses led to the inference that this age-0 cohort experienced little mortality during the winter of 1998–99. We used a regression model to quantify risk of winter starvation for the 1998 cohort, using 1981–2001 winter water temperatures from southeastern Lake Michigan. This analysis suggested that risk of starvation for the 1998 cohort across this period was low (1.0–4.4%). Back calculation and regression analyses allow us to reject the hypothesis that reduced growth led to a high rate of winter mortality for the 1998 cohort. If we extrapolate our findings to past cohorts, the results would be similar unless these fish were significantly smaller than the 1998 cohort. Variation in age-0 length, growth, or winter mortality failed to fully explain yellow perch recruitment patterns in southeastern Lake Michigan. We hypothesize that factors acting before the juvenile stage is sampled during summer are shaping recruitment; resolving this requires further, stage-specific studies.

Influence of Introduced Spawning Habitat on Yellow Perch Reproduction in Lake Madison, South Dakota

ABSTRACT Yellow perch (Perca flavescens Mitchill) populations often exhibit variable recruitment in eastern South Dakota. Lakes with erratic yellow perch recruitment are shallow and lack structure; consequently, habitat manipulation may be useful to enhance perch recruitment. The objective of this study was to determine the contribution of eggs deposited on a conifer tree reef toward overall larval yellow perch production in Lake Madison. The number of egg masses deposited on the reef and the mean number of eggs per mass were calculated and used to estimate the number of larvae produced on the reef. Peak abundance of larvae in the lake was estimated using a surface trawl. Results from two years indicated that the reef contributed 14 to 37% toward larval yellow perch production, although confidence intervals were large. Low numbers of egg masses observed per tree (0.13 to 0.44) relative to other studies lead us to conclude that several smaller reefs might have been a better design than a single, large reef.

Zooplankton Selectivity by Larval Yellow Perch in Green Bay, Lake Michigan

Recruitment of yellow perch ( Perca flavescens) in southern Lake Michigan has been poor since 1989, whereas in Green Bay, Lake Michigan, larval yellow perch have been more abundant. Therefore, investigation of factors influencing yellow perch early life stages in Green Bay, and comparison with southern Lake Michigan conditions, can lend insight into factors limiting recruitment of this species in southern waters of the lake. We investigated diets and selectivity of larval yellow perch in Green Bay, to identify conditions of zooplankton availability that limit larval yellow perch. Larval yellow perch and zooplankton were collected in Green Bay during May and June 1998 and 1999. We identified, counted, and measured available zooplankton and larval yellow perch stomach contents, estimated larval gape size, and compared larval diets to zooplankton availability. Similarities between 1998 and 1999 in larval yellow perch diet composition and selectivity indicate that zooplankton are most likely to limit small (< 8 mm TL), gape-limited larvae, whose diets are comprised almost exclusively of copepod nauplii and small (< 0.5 mm) copepods. Differences between 1998 and 1999 further implicate the importance of small copepods. In 1999, when small copepods were less abundant in Green Bay than in 1998, a higher proportion of larvae had empty guts, and growth of larvae was slower. In southern Lake Michigan, densities of small copepods have declined precipitously since the late 1980s. Taken together, our findings indicate that availability of suitable prey for larval yellow perch in Lake Michigan warrants further investigation as a potential factor limiting recruitment during the last decade.

Exploring Zooplankton Changes in Southern Lake Michigan: Implications for Yellow Perch Recruitment

Recruitment of fishes frequently depends in part on availability of appropriate densities and sizes of zooplankton prey. In Lake Michigan, yellow perch ( Perca flavescens) have experienced poor recruitment since 1989, although the mechanisms driving this poor recruitment have not been identified. To explore the possible influence of zooplankton density available for yellow perch larvae shortly after hatching on eventual recruitment success of age-0 yellow perch, we examined patterns of nearshore zooplankton and age-0 yellow perch relative abundance in southwestern Lake Michigan during June 1988-1990 and 1996-1998. Zooplankton density, mean size, and biomass that were available to newly hatched yellow perch larvae in June declined from the late 1980s to the late 1990s, suggesting that one or more of these declines may contribute to the current reduced rate of yellow perch recruitment seen in southwestern Lake Michigan. A strong positive linear relationship existed between the density of zooplankton present during June, the time when first-feeding larvae appear, and CPUE of age-0 yellow perch in a given year. A laboratory experiment revealed that more zooplankton does increase larval yellow perch survival, supporting the field pattern. Therefore, zooplankton availability for larvae can be an important determinant of yellow perch recruitment success in Lake Michigan and should be considered in addition to other mechanisms when evaluating the factors regulating recruitment of this species.

Relationship between Alewife Abundance and Yellow Perch Recruitment in Southern Lake Michigan

Abstract We examined the relationship between the abundance of alewives Alosa pseudoharengus and the recruitment of yellow perch Perca flavescens to determine if alewives were potentially responsible for yellow perch recruitment failures in southern Lake Michigan after 1988. We used annual Jun–Aug bottom trawl data from two 5-m-depth index sites near Michigan City, Indiana, during 1984–1998 to index alewife abundance as the catch per unit effort (CPUE) of age-1 and older fish and yellow perch recruitment as the CPUE of age-2 fish. The relationship between alewife abundance and yellow perch recruitment was modeled as logeRt +2 = 11.7 − (2.12) logeAt, where logeRt +2 is the natural log of the CPUE of age-2 yellow perch in year t + 2 and logeAt is the natural log of the CPUE of alewives age 1 and older in year t. The model explained greater than 70% of the variability in recruitment of the 1984–1996 yellow perch year-classes. We conclude that yellow perch year-class failures in Indiana waters of Lake Michiga...

Evidence of predatory control of yellow perch (Perca flavescens) recruitment in Lake Erie, U.S.A.

Evidence of predatory control of yellow perch (Perca flavescens) recruitment in Lake Erie, U.S.A.

Evidence of predatory control of yellow perch (Perca flavescens) recruitment in Lake Erie, U.S.A.

Predation can be a major factor in recruitment success of yellow perch (Perca flavescens Mitchitl). Trawl catches of age‐0 yellow perch in western Lake Erie declined from 870·3 per trawling h in June to 3·3 per trawling h in late July 1988. Coincident with the decline in relative abundance of age‐0 yellow perch we found large numbers of age‐0 yellow perch in the stomachs of small walleyes (Stizostedion vitreum Mitchill). From this evidence we hypothesized that predation by walleyes may have caused the demise of the 1988 year‐class of yellow perch. We used a population and bioenergetics modelling approach to estimate the impact of walleye predation on the abundance of age‐0 yellow perch. Modelling showed that 6·8 × 109 age‐0 yellow perch that had attained 18 mm total length (t.l.), were eaten by small (age‐2 and younger) walleye from June through July 1988. We estimated that walleye ate 28·4–89·7% of the yellow perch reaching 18 mm t.l. during 1988. The majority of this predation (77% of total) was by the abundant age‐2 cohort of walleyes. We concluded that, even in a large system such as Lake Erie, predation can play a major role in structuring year‐class strength of yellow perch and, thus, management of percid fisheries should be conducted on a fish‐community basis.

Recruitment of Yellow Perch ( Perca flavescens) Affected by Stock Size and Water Temperature in Lakes Erie and St. Clair, 1965–85

Two influences on recruitment of yellow perch ( Perca flavescens) were considered: parental stock size and spring water temperatures. The data for this analysis were obtained from two sources. First, from samples of trawl catches (near bottom) from April to October (1965–85) in the western, central, and eastern basins of Lake Erie, and from Lake St. Clair and second, from gillnet catches from April to July in the three basins of Lake Erie (1978–86). The relative abundances (CPUE) of stocks in these study areas were as follows: western > St. Clair > eastern > central basin. Degree-days and mean water temperatures of the basins were ranked as follows: St. Clair > western > central > eastern basin. Rates of warming of water were greatest in the western basin, followed by St. Clair, central basin, and eastern basin. The rates of increase in water temperature (April to June) were positively related to average water temperatures and total degree-days (above 0°C. Only in the western basin of Lake Erie could the variations in recruitment to age 1+ be apportioned to the effect of parental stock size (12%) and water warming in the spring (51%). Recruitment at age 0+ (young-of-year(YOY)) was explained also by both warming rate (17%) and parental stock size (12%) for the samples from the western basin. The pooled data obtained from samples of catches in the gillnets indicated that only parental stock size (19%) determined the abundance of perch at age 1+ yrs-old. The relative abundance of yearlings was related to the abundance of YOY perch in the previous year in only the central and western basins (trawl sample). The dependence of recruitment on the density of the parental stock was evident from the regression of the ratio of recruits (age 1 +) to spawners on parental stock size in the combined trawl samples from Lakes Erie and St. Clair, and in the separate samples from the eastern and central basins of Lake Erie and Lake St. Clair. Similarly, recruitment at age 0+ (YOY) was also shown to be density-dependent in all but the western basin of Lake Erie. The coefficients obtained by regressing recruitment (0 +, 1 + years) on stock size were significant and less than 1 in the pooled sample from the western basin and St. Clair, indicating density-dependent recruitment.

Predation by Alewives on Larvae of Yellow Perch in Lake Ontario

Alewives Alosa pseudoharengus preyed upon larval yellow perch Perca flavescens during late April and early May in a Lake Ontario embayment. Based on stomach analyses of 1,308 alewives collected during the springs of 1984–1986, predation on larval yellow perch occurred primarily at night in littoral areas during the 2 weeks immediately following peak hatch of yellow perch. Among stomachs of all alewives caught at night in littoral areas, 30% in 1985 (N = 43) and 41% in 1986 (N = 71) contained yellow perch larvae. Mean numbers of whole larvae per alewife stomach were 3.8 in 1985 and 32.6 in 1986. As many as 361 intact larval yellow perch were found in one stomach. Mean total lengths of yellow perch consumed on two dates in mid-May 1986 were 7.3 and 7.6 mm, compared to mean sizes of 8.0 and 8.6 mm of larvae living within the bay. We suggest predation by alewives on yellow perch larvae may reduce yellow perch recruitment in Lake Ontario as well as in other Great Lakes.

Factors affecting growth and recruitment of yellow perch, Perca flavescens Mitchill, in South Bay, Lake Huron

Five hypotheses explaining variations in growth and recruitment were tested statistically with data from a study of yellow perch, Perca flavescens, 1950–83. Recruitment was not a function of water temperature during spawning, hatching or the first year, but was a function of lake water levels. Growth was not related to average water temperatures or degree‐days, but was inversely correlated with the abundance of year‐classes.