Density dependence in total egg production per spawner for marine fish     

Akinori Takasuka  Michio Yoneda  Yoshioki Oozeki 《Fish and Fisheries》2019,20(1):125-137

A paradigm of fisheries science holds that spawning stock biomass (SSB) is directly proportional to total egg production (TEP) of fish stocks. This “SSB–TEP proportionality” paradigm has been a basic premise underlying the spawner–recruitment models for fisheries management and numerous studies on recruitment mechanisms of fish. Studies on maternal effects on reproductive potential of a stock have progressed during the last few decades, leading to doubt concerning the paradigm. Nonetheless, a direct test of the paradigm at multidecadal scales has been difficult because of data limitations in the stock assessment systems worldwide. Here, we tested the paradigm for marine fish based on a novel combination of two independent 38‐year time series: fishery‐dependent stock assessment data and fishery‐independent egg survey data. Through this approach, we show that the SSB–TEP proportionality is distorted by density dependence in total egg production per spawner individual (TEPPS) or spawner unit weight (TEPPSW) at a multidecadal scale. The TEPPS/TEPPSW exponentially declined with biomass and thus was density‐dependent for Japanese sardine, a small pelagic species exhibiting a high level of population fluctuation, in the western North Pacific. By contrast, the TEPPS/TEPPSW was sardine‐density‐dependent for Japanese anchovy, another small pelagic species exhibiting a moderate level of population fluctuation well‐known for being out of phase with sardine. Our analysis revealed intraspecific (sardine) and interspecific (anchovy) density dependence in TEPPS/TEPPSW, which was previously unaccounted for in spawner–recruitment relationships. Such density‐dependent effects at the time of spawning should be considered in fisheries management and studies on recruitment mechanisms.  相似文献   

Species identification of Alaska pollock,Gadus spp., and Micromesistius spp. in cod roe products using a PCR-based method     

Namikoshi  Atsushi  Takashima  Yasuharu  Iguchi  Jun  Yanagimoto  Takashi  Yamashita  Michiaki 《Fisheries Science》2011,77(4):671-678

Fish species identification techniques for authentic food labeling were developed using species-specific PCR primers for cod roe products. A salted, seasoned fish roe product, karashimentaiko (chilli cod roe), is produced from the eggs of Alaska pollock, Theragra chalcogramma, according to the fair trade competition agreement authorized by the Fair Trade Commission of the Japanese government. To examine whether Alaska pollock ovaries or those of other fish species are being used as raw materials for the fish roe products, we developed species identification techniques using PCR amplification of a 255-bp fragment encoding the mitochondrial ATP synthase Fo subunit 6 (ATP6) gene with a species-specific primer set for Alaska pollock mitochondrial DNA. We also designed two species-specific primer sets corresponding to the mitochondrial ATP6 and cytochrome b (cytb) for Gadus spp. and Micromesistius spp. by PCR amplification of 332- and 223-bp fragments, respectively. We examined the species specificity of these PCR-based methods among nine commercially important Gadidae species.  相似文献   

Optimal period for the effective promotion of initial swim bladder inflation in yellowfin tuna,Thunnus albacares (Temminck and Schlegel), larvae          下载免费PDF全文

Tomoki Honryo  Michio Kurata  Angel Guillen  Yoshiki Tamura  Amado Cano  Maria S Stein  Daniel Margulies  Vernon P Scholey  Yoshifumi Sawada 《Aquaculture Research》2017,48(10):5443-5446

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