Biological Characteristics of Nearshore Fishes of California: Final Report

A Review of Existing Knowledge and Proposed Additional Studies for the Pacific Ocean Interjurisdictional Fisheries Management Plan Coordination and Development Project

Submitted to Mr. Al Didier
Pacific States Marine Fisheries Commission
August 31, 2000

Table of Contents

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Project Summary

As part of the recent Marine Life Management Act, the California Department of Fish and Wildlife is required to produce a Fishery Management Plan for the nearshore region as described in the Nearshore Fisheries Management Act. This requires the compilation of a species list that includes the species of fishes for which size limits are prescribed in the Act and other vulnerable species, and a detailed analysis of existing knowledge of the life history (age, growth, age at maturity, age composition, habitat utilization, reproduction, recruitment, trophic relationships, population health, and stock structure, including genetics) of nearshore fish species, especially those subject to the newly developing live fish (premium) fishery. During this project, we compiled a list of species currently taken in the nearshore fishery and others that could be particularly vulnerable (n=124). In addition, we created a life history parameter questionnaire to guide our literature search and compilation of life history parameters, surveyed the existing literature, constructed a life history database of the nearshore fish species list, and compiled a literature cited document. General gaps in the existing knowledge are identified, and specific research projects are proposed on such subjects as age at maturity, age validation, reproduction, trophic interactions, genetic variance, and mobility of fish stocks subject to the nearshore fisheries of California. It is hoped that this project will result in additional support to answer questions that will provide management agencies with sufficient information to effectively manage this fishery.

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The 1998 Keeley Bill (AB 1241), which is now law as the Marine Life Management Act (MLMA), has several requirements, including size limits for selected species, and status reports and Fishery Management Plans (FMPs) to be prepared by the California Department of Fish and Wildlife (CDFW) for important commercial and sport fishery species in California. Funding has been made available from the Pacific States Marine Fisheries Commission (PSMFC) to support a research institution (Moss Landing Marine Labs, MLML) to complement the work CDFW is doing on this subject.

Nearshore fisheries have existed in California for decades (Lea et al. 1999), but a recent fishery for live fish that are used in the restaurant business and shipped overseas, started in southern California in the late 1980s, spread to northern California in the early 1990s, and now has become common in central California (McKee-Lewis 1996). The fishery uses gear ranging from hook and line to pole fishing and traps. The landings of live finfish in California have exhibited an exponential increase from ~ 20,000 to 1,200,000 pounds in the past 7 years, and were worth from ~ $20,000 to $1,300,000. The number of species landed in this fishery range from ~5 to > 50, depending upon location, season, and year. Even though some reports of landings and the status of this fishery exist (CDFW 1998, Starr et al. 1998) much information is still needed.

The role of life histories in this nearshore fishery has not yet been evaluated. Could the live fish fishery be doomed to failure because it targets mainly on small, immature specimens of shallow, nearshore fishes, some of which are not targeted in any other way? Certainly, fisheries for juvenile fishes, especially if they target all areas where these juveniles live, cannot last long. The large and increasing numbers of fishes being harvested before most get a chance to reproduce for the first time is of particular concern regarding the live fish fishery. Since rockfish are typically longlived, often take many years to mature (Echeverria 1987, Love and Johnson 1998, Lea et al. 1999), and are known to have highlyvariable, successful recruitment (Karpov et al. 1995), harvesting most individuals before they mature and reproduce can be disastrous for their populations and ultimately the ecosystem.

The live fish fishery targets on sizes and species of fishes that were not heavily fished prior to now (Lea et al. 1999). It is known that many of these nearshore fishes are very siteintensive. Thus, any heavy fishing on their populations, most of which have either home sites or territories and do not move much after settling, could be very deleterious to the local population densities.

In June 1999, the University of California Sea Grant Marine Advisory Program and CDFW sponsored a Workshop on Assessing and Managing Nearshore Fisheries in Santa Barbara. Many fishery biologists attended this useful workshop and produced numerous recommendations, including the need to obtain the best possible data on catch, effort, species and size composition, reproduction, maturity, location, site specificity, larval dispersal and recruitment, and socio-economic variables to enable CDFW to evaluate the trends in this increasing fishery.

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Work Accomplished

The results from this project will be a major step toward characterizing the fish assemblages in California's nearshore ocean waters and providing essential information for measuring the impacts of human activities, measuring economic costs and benefits to the state from commercial and recreational fishing, and evaluating alternative management strategies for marine fisheries through the FMP process. These results are expected to enhance the quality, availability, and consistency of life history data used in CDFW management decisions, and to make these data available to the public and other government or private academic institutions. This research will complement a separate state-funded nearshore marine Geographic Information System (GIS) project to start mapping nearshore sedimentary and rocky habitats in 0-30 meters off California and classify these bathymetric habitats and their species associations.

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A. Analysis and Summary of Existing Life History Parameters

The most recent analyses of the knowledge of the life histories of and status of fisheries for species taken in the nearshore fishery was accomplished by Leet et al. (1992) for California and by Starr et al. (1998) and Lea et al. (1999) for central California. Much information about life histories of these species is scattered about the published literature, as well as contained in state and federal agency reports that have not been published in refereed journals or made publicly available. The MLMA has specific size limits for a select group of fish species targeted by the live fish fishery, yet an examination of the published literature on these species does not provide age estimates and reproductive maturity information that supports all of these size limits. Therefore, a review and compilation of the existing information is imperative.

  1. Species List

    The first objective was to produce a list of the species now taken in the nearshore fisheries of California. This list includes the species listed in the MLMA, but also includes species frequently caught that are not on this size limit list and those which could be particularly vulnerable. Among personnel at MLML and Bob Lea from CDFW, we decided on a list of species having some or one of the following criteria: 1) occurring in 40 fathoms or less; 2) listed in the MLMA; 3) listed in McKee-Lewis (1996); 4) common in the sport fishery; 5) common as bait fish; 6) common in public aquaria or the aquaria trade; 7) common as bycatch and prone to overfishing; or 8) marketed incorrectly and possibly prone to overfishing. These criteria could, of course, include almost all of the nearshore fishes off the coast of California. Therefore, our species list was subjectively honed down from >239 to 124 species (42 families); a relatively reasonable number of species to survey during this 8-month project (Table 1).

  2. Literature Survey

    The second objective was to survey the existing published literature on those subjects recently included in the Fisheries Management Plan (FMP) and Biological Information Catalog system being developed by David VenTresca (CDFW, Monterey). Life history subjects in our survey include, but are not limited to, age and growth (length/weight/age relationships, growth parameters, longevity, age composition); spawning and reproductive status (parturition period, size/age at sexual maturation, fecundity); recruitment (size at settlement, recruitment to fisheries); population or stock genetics; mortality estimates (natural, fishing, total); species-habitat associations; trophic interactions (feeding, predation); and behavior (competition, movements, home ranges). We constructed a Life History Questionnaire (Appendix A) (PDF) to guide our literature search, and used this questionnaire to compile life history parameters into a Flat Database (Microsoft Excel Workbook: life_histories.xls).

  3. Database Format

    To read, understand, and utilize the database and its format, the Life History Questionnaire (Appendix A) should be used while viewing the database. The Flat Database is composed of 32 Microsoft Excel Worksheets within a Single Workbook (life_histories.xls). Worksheets are organized by family name or species group (elasmobranchs and flatfishes only). Within a spreadsheet, species are listed in rows within column B (Scientific name). Life history parameter categories are listed at the top of the spreadsheet(s) from left to right (following the order of the Life History Questionnaire, Appendix A), columns A thru DG (or DH, in some cases). Life history information is then contained within spreadsheet cells. Abbreviations used in the database are listed at the end of Appendix A. The literature source for each life history parameter is listed at the bottom of each column. Therefore, the citations are column-specific, and are footnoted accordingly (i.e. renumbered for each column). The corresponding literature can be found in the Literature Cited document (Appendix B) (PDF), where citations are alphabetized.

    In some cases, life history categories are related; therefore, information is listed across a single row (encompassing several columns). For example, the "von Bertalanffy Growth Parameters " section within "Age and Growth" encompasses several columns (from "Geographic Area" to "Verification"); and data within one row (across 16 columns) will refer to one study. Other similar formats are found in the "Maturity," "Fertilization and Spawning Period," "Habitat Association & Trophic Interactions," "Genetic Variance," "Recruitment Into Fishery," and "Mortality" sections. Other columns stand alone, and footnoted citations may not correspond across a row, from column to column.

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B. Identification of Gaps in the Existing Knowledge of Life History Parameters for Nearshore Fish Species

The database serves not only as an information source, but also serves to identify where information is lacking. To clarify and identify true gaps in the literature, three abbreviations were used where information was not provided: 1) NA, not applicable; 2) NG, not given; or 3) NF, not found. Not applicable (NA) refers to a life history parameter that is not valid for a species (e.g. egg stage not applicable for embiotocids). Not given (NG) refers to a study where similar life history parameters are provided within a section of the survey, but not for the specified parameter (e.g. an age and growth study where von Bertalanffy growth parameters are provided for males and females but not for the sexes combined; or a maturity study with age at first maturity but not age at 50% maturity). Not found (NF) refers to a parameter where no information was found; either it does not exist, or we did not find the information. Therefore an empty space or cell does not mean a lack of information, rather a space for formatting.

There are many gaps in the existing life history literature of California's nearshore fishes.

In general, the following life history information is lacking for most species:

  1. age validation and growth studies
  2. fecundity estimates
  3. measures of genetic variance
  4. size and age at settlement
  5. mortality estimates
  6. recruitment to the fishery
  7. movement

Large gaps in the existing knowledge of life history parameters occur primarily for elasmobranchs, and for the families Cottidae, Hexagrammidae, Muraenidae, Anoplopomatidae, Sphyraenidae, Pleuronectidae, Bothidae, Polyprionidae, Carangidae, Anarhichadidae, Scorpaenidae (several species), and Embiotocidae (especially age validation). Several specific gaps are identified below in Part C.

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C. Additional Studies on the Life History of Nearshore Fishes

Following Goals A and B, we are pursuing our third goal, much of which will comprise the bulk of the funding we have requested from PSMFC for 2000-2001, which will be to continue some of the research that we initiated in the first year's project and to add several other interesting and important projects.

1. Age and Growth, Longevity, and Age at First Maturity of Selected MLMA/NFMA Species

The first objective will be to initiate age and growth, reproduction, and age-at-maturity studies on some of the species for which there is uncertainty about the relationship between MLMA size limits and verified or validated estimates of age. Our literature review this year indicated that some of the size limits did not agree well with existing knowledge of the age at first maturity for some species. To determine how vulnerable some of the nearshore fish stocks are to exploitation, an idea of their longevity, based on these proposed validated age and growth studies and coupled with better estimates of natural and fishing mortality and fecundity of older/larger age classes, will result in better information for nearshore fishery management.

One of the species that requires the most urgent attention is the cabezon (Scorpaenichthys marmoratus), which despite being quite abundant and popular in historic recreational fisheries, has not been very thoroughly studied, especially in California (O'Connell 1953; Lauth 1987, 1988). We propose to concentrate on age and growth studies that utilize more modern techniques that involve sectioning, and we will conduct marginal increment analysis to validate the growth, age at maturity, and longevity of this important nearshore species. To determine length at maturity, the size and degree of maturity of the gonads will be examined throughout the year. Cabezon are being collected from northern and southern California to determine if differences exist between fish from these two geographic areas. These data will provide valuable information for fishery management.

Other species (see list below under genetics and demography) will be studied in next year's PSMFC project, and will concentrate on age, growth, reproduction and age-at-maturity studies. Inclusion of additional species in this list will depend upon the samples available and the graduate student's interest in them as thesis material.

Dr. Ralph Larson (SFSU) and his graduate students analyzed existing and newly collected samples of otoliths and morphometric data from kelp rockfish (Sebastes atrovirens) and black and yellow rockfish (S. chrysomelas) as part of their on-going studies of age and growth of these two species.

2. Genetics and Demography

A comparative life history study of blue rockfish (Sebastes mystinus) subpopulations will be performed at five sites along California: 1) Santa Barbara mainland, 2) San Miguel Island, 3) central California (Big Creek or Monterey Bay), 4) the Farallon Islands, and 5) northern California (Mendocino or Bodega Bay). Genetic analyses of tissue samples, using the control region (D-loop) of mitochondrial DNA, will be used to measure genetic variance and population substructure among geographic sites. In addition, a stage-based (larvae, pelagic juvenile, settled juvenile, and adult) stochastic demographic model will be produced using age and growth information, adult mortality (estimated from VBGF parameters and gonadal indices), age at first maturity, and longevity estimates from each geographic area. This model will provide vital statistics-- such as intrinsic rates of increase and rebound potentials--for each subpopulation (Caswell 1989, Au and Smith 1997).

The combination of both genetic and demographic measures of each subpopulation will allow a better understanding of population "health," adaptability, and longevity (Lacy 1987, Lande 1988, Nunney 1992, Soltis et al. 1999). This unique combination will also provide insight into nearshore rockfish genetic relatedness in the California Current and the effectiveness of marine reserves to protect residential nearshore species with long larval durations. This approach will be a further attempt to formulate an index, which may be comparable across taxa and populations.

The blue rockfish was chosen as the model species to represent the nearshore rockfish complex, because sufficient samples are obtainable; whereas, local population depletions and the solitary nature of other species (S. atrovirens, S. auriculatus, S. carnatus, S. caurinus. S. chrysomelas, and S. rastrelliger) makes obtaining sufficient numbers of samples more difficult. Although this study will focus on California blue rockfish populations, its results and the general approach will be applicable to fishes with similar life histories. The proposed index will also provide a means of comparison for fisheries managers to evaluate sub-stock structure and interactions.

3. Seasonal Reproductive Timing of Nearshore Fish Species

Simply setting size limits does not insure that reproductively capable and/or active females are protected sufficiently. For example, there is some disagreement in the literature on the size and age at maturity of the leopard shark, Triakis semifasciata (Smith and Abramson 1990, Cailliet 1992, Kusher et al. 1992, Au and Smith 1997, and Smith et al. 1998). Thus, the California size limit may not protect female leopard sharks so that they can successfully reproduce before entering the fishery. Likewise, without seasonal closure for some species of nearshore rockfishes during their spawning season (Echeverria 1987), it is possible that fishing pressure could deleteriously affect reproductively capable females, unless there were closed seasons during that period of time.

In response to this need, we will study the reproductive cycle and stage of maturity of the leopard shark by monitoring steroid concentrations in their blood. The purpose of this study will be to examine the serum steroid hormones in female leopard sharks. Previous studies have correlated 17ß-estradiol, progesterone, testosterone, and dihydrotestosterone with reproductive events (Rasmussen and Gruber 1993, Rasmussen and Gruber 1990, Heupel et al. 1999, Koob and Callard 1999, Rasmussen et al. 1999). Blood samples will be taken seasonally in several estuaries along the central California coastline and analyzed using radioimmunoassays. Monitoring of reproductive hormones can provide information regarding reproductive mode, gestation, frequency of pregnancy and location of breeding areas. These details are critical in formulating effective management of these fisheries (Pratt and Otake 1990). Future extension of this kind of research will prove useful to many other groups of nearshore fishes, especially the viviparous rockfishes, for which seasonal closure might be an effective management tool.

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Investigators and Research Staff

Principal Investigator:

Dr. Gregor M. Cailliet, Professor
Moss Landing Marine Laboratories
8272 Moss Landing Road
Moss Landing, California 95039
(831) 632-4432; fax (831) 632-4403

MLML Research Staff:

Erica J. Burton, Project Leader;
Jason M. Cope, Graduate Research Assistant;
Lisa A. Kerr, Graduate Research Assistant;
Moss Landing Marine Laboratories
8272 Moss Landing Road
Moss Landing, California 95039
(831) 632-4419; fax (831) 632-4403


Dr. Ralph J. Larson, Professor
Department of Biology
San Francisco State University
San Francisco, California 94132
(415) 338-1027

Dr. Robert N. Lea
California Department of Fish and Wildlife
20 Lower Ragsdale Drive, Suite 100
Monterey, California 93940
(831) 649-2835; fax (831) 649-2894

Mr. David VenTresca
California Department of Fish and Wildlife

Mr. Eric Knaggs
California Department of Fish and Wildlife
20 Lower Ragsdale Drive, Suite 100
Monterey, California 93940
(831) 649-7193; fax (831) 649-2894