Oil-to-meal ratios of pelagic fish taken from the northern and the southern Benguela systems: seasonal patterns and temporal trends, 1951–1993

Schülein, F. H.; Boyd, A. J.; Underhill, Les G.

doi:10.2989/02577619509504834

Cited by 16 publications

(8 citation statements)

References 6 publications

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“…Such databases are often collected systematically for industrial purposes (Schülein et al, 1995) and constitute a relatively underutilized data source.…”

Section: Discussionmentioning

confidence: 99%

Developing Alternative Indices of Reproductive Potential for Use in Fisheries Management: Case Studies for Stocks Spanning an Information Gradient

Marshall¹,

O’Brien²,

Tomkiewicz³

et al. 2003

J. Northw. Atl. Fish. Sci.

134

137

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There is accumulating evidence to suggest that spawning stock biomass (SSB) may not be directly proportional to reproductive potential. The wide-ranging implications of this conclusion necessitate that it be tested for as many stocks as possible. Undertaking such tests is complicated by the fact that fish stocks vary in the amount and type of information that is available to estimate reproductive potential. In this review, nine stocks illustrate the range of J. Northw. Atl. Fish. Sci., Vol. 33: 161190 1 Present address: University of Aberdeen, Zoology Dept., Tillydrone Ave., Aberdeen, AB24 2TZ, Scotland, UK. Fish. Sci., Vol. 33, 2003 162 approaches that are being taken to developing alternative indices of reproductive potential from existing data resources. Three stocks had sufficient data to reconstruct a time series of total egg production (TEP), whereas, the remaining stocks were limited to estimating proxies for stock reproductive potential. For some of the case studies the alternative indices explained a higher amount of recruitment variation than did SSB. Other case studies provided evidence that characteristics of the spawning stock, e.g. age diversity and female-only SSB, influence recruitment in ways that are not properly accounted for by using SSB as the sole index of reproductive potential. This is further evidence that the assumption of proportionality between SSB and TEP is invalid. The data-rich stocks showed the relationship between SSB and TEP to be variable and characterized by distinct time trends. This variability will impact the ability of biomass-based reference points to conserve reproductive potential. Consequently, management protocols should be adapted to incorporate the detailed information on reproductive potential that is increasingly becoming available rather than being restricted to approaches that have been designed for data-poor situations.

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“…Such databases are often collected systematically for industrial purposes (Schülein et al, 1995) and constitute a relatively underutilized data source.…”

Section: Discussionmentioning

confidence: 99%

Developing Alternative Indices of Reproductive Potential for Use in Fisheries Management: Case Studies for Stocks Spanning an Information Gradient

Marshall¹,

O’Brien²,

Tomkiewicz³

et al. 2003

J. Northw. Atl. Fish. Sci.

134

137

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show abstract

“…Measurements that are highly resolved in space and time pose a considerable logistical challenge; however, many of the existing high-resolution condition databases were developed in support of or by commercial fisheries. For example, industrial sources of information have been used to derive monthly condition indices for pelagic stocks in the Southern California region (Parrish and Mallicoate 1995) and Benguela system (Schülein et al 1995).…”

Section: Discussionmentioning

confidence: 99%

“…Condition influences the reproductive potential of a stock via its effects on maturation (Henderson and Morgan 2002), fecundity (Hislop et al 1978;Kjesbu et al 1998;Lambert and Dutil 2000), atresia (Ma et al 1998;Óskarsson et al 2002;Kurita et al 2003), egg size (Kjesbu 1989;Chambers and Waiwood 1996;Marteinsdottir and Steinarsson 1998), egg density (Saborido-Rey et al 2003), yolk volumes (Morimoto 1996), hatching success (Laine and Rajasilta 1999), and larval survival (Marteinsdottir and Steinarsson 1998). Because of the cumulative impact on reproduction, there have been several suggestions that condition can influence recruitment for both pelagic and demersal species (Kawasaki and Omori 1995;Schülein et al 1995;Marshall and Frank 1999).…”

Section: Introductionmentioning

confidence: 99%

Deriving condition indices from standard fisheries databases and evaluating their sensitivity to variation in stored energy reserves

Marshall¹,

Needle²,

Yaragina³

et al. 2004

Can. J. Fish. Aquat. Sci.

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Abstract:To evaluate interstock differences in condition, it would be advantageous to develop stock-level condition indices from standardized databases on weight and length. This study describes a method for estimating stock-level condition when individual-level observations on length and weight are not easily accessible. For each year in a 56-year time series for Northeast Arctic cod (Gadus morhua), pseudo-observations of weight and length were generated by pairing the Norwegian and Russian values for weight-at-age provided annually to the assessment working group with estimates of length-at-age derived from the same databases. A weight-length relationship fit to each year was then used to predict weight-at-length, i.e., girth, for a range of standard lengths (30-120 cm). This index was uncorrelated with both the liver condition index and the abundance of Barents Sea capelin (Mallotus villosus), suggesting that at the stock level, the girth of cod is not necessarily indicative of the magnitude of stored energy reserves. Partitioning body size into length-at-age and girth revealed long-term trends in body size. In particular, large/old cod showed substantially higher values of both length-at-age and girth that could be the result of long-term increases in fishing mortality.

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“…see review in Dalsgaard et al 2003), the biochemical ecology of marine food webs from low-latitude temperate zones, where the major pelagic fisheries and upwelling systems are located, has surprisingly been overlooked, and related studies are scarce (Schülein et al 1995, Paiting et al 1998. In fact, biochemical indicators can provide major insights into the mechanisms controlling the abundance of small pelagic fishes, since they integrate the impacts of environmental forcing on feeding and are directly linked to fitness, thus offering a powerful complement to traditional indicators (e.g.…”

Section: Abstract: Sardina Pilchardus · Sardines · Proximate Composimentioning

confidence: 99%

Bioenergetics of small pelagic fishes in upwelling systems: relationship between fish condition, coastal ecosystem dynamics and fisheries

Rosa¹,

González²,

Broitman³

et al. 2010

Mar. Ecol. Prog. Ser.

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Oil-to-meal ratios of pelagic fish taken from the northern and the southern Benguela systems: seasonal patterns and temporal trends, 1951–1993

Cited by 16 publications

References 6 publications

Developing Alternative Indices of Reproductive Potential for Use in Fisheries Management: Case Studies for Stocks Spanning an Information Gradient

Developing Alternative Indices of Reproductive Potential for Use in Fisheries Management: Case Studies for Stocks Spanning an Information Gradient

Deriving condition indices from standard fisheries databases and evaluating their sensitivity to variation in stored energy reserves

Bioenergetics of small pelagic fishes in upwelling systems: relationship between fish condition, coastal ecosystem dynamics and fisheries

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