National Marine Fisheries Service

About: National Marine Fisheries Service is a government organization based out in Silver Spring, Maryland, United States. It is known for research contribution in the topics: Population & Fisheries management. The organization has 3949 authors who have published 7053 publications receiving 305073 citations. The organization is also known as: NOAA Fisheries & NOAA National Marine Fisheries Service.

A fish of many scales: extrapolating sublethal pesticide exposures to the productivity of wild salmon populations.

Abstract: For more than a decade, numerous pesticides have been detected in river systems of the western United States that support anadromous species of Pacific salmon and steelhead. Over the same interval, several declining wild salmon populations have been listed as either threatened or endangered under the U.S. Endangered Species Act (ESA). Because pesticides occur in surface waters that provide critical habitat for ESA-listed stocks, they are an ongoing concern for salmon conservation and recovery throughout California and the Pacific Northwest. Because pesticide exposures are typically sublethal, a key question is whether toxicological effects at (or below) the scale of the individual animal ultimately reduce the productivity and recovery potential of wild populations. In this study we evaluate how the sublethal impacts of pesticides on physiology and behavior can reduce the somatic growth of juvenile chinook salmon (Oncorhynchus tshawytscha) and, by extension, subsequent size-dependent survival when animals migrate to the ocean and overwinter in their first year. Our analyses focused on the organophosphate and carbamate classes of insecticides. These neurotoxic chemicals have been widely detected in aquatic environments. They inhibit acetylcholinesterase, an enzyme in the salmon nervous system that regulates neurotransmitter-mediated signaling at synapses. Based on empirical data, we developed a model that explicitly links sublethal reductions in acetylcholinesterase activity to reductions in feeding behavior, food ration, growth, and size at migration. Individual size was then used to estimate size-dependent survival during migration and transition to the sea. Individual survival estimates were then integrated into a life-history population projection matrix and used to calculate population productivity and growth rate. Our results indicate that short-term (i.e., four-day) exposures that are representative of seasonal pesticide use may be sufficient to reduce the growth and size at ocean entry of juvenile chinook. The consequent reduction in individual survival over successive years reduces the intrinsic productivity (lambda) of a modeled ocean-type chinook population. Overall, we show that exposures to common pesticides may place important constraints on the recovery of ESA-listed salmon species, and that simple models can be used to extrapolate toxicological impacts across several scales of biological complexity.

Proximate composition of some north-eastern Pacific forage fish species

Abstract: To understand the relative dietary value of forage fish as prey in the Bering Sea and Gulf of Alaska, whole organisms of 13 species were analysed for proximate composition (protein, oil, ash and moisture content). Eulachon (Thaleichthys pacificus) were high in oil (total lipid) (16.8% to 21.4%) and low in moisture (64.6% to 70.8%). Oil in capelin (Mallotus villosus) ranged from 2.1% to 14.0%. Juveniles of walleye pollock (Theragra chalcogramma), Atka mackerel (Pleurogrammus monopterygius), Pacific herring (Clupea pallasii), and prowfish (Zaprora silenus) had low oil contents ( 80.3%). Rankings of median proximate values illustrate the similarities. Surf smelt (Hypomesus pretiosus), rainbow smelt (Osmerus mordax), pricklebacks (Lumpenus spp.), Atka mackerel, Pacific sand lance (Ammodytes hexapterus) and Pacific sandfish (Trichodon trichodon) ranked high in median protein content (> 15.4%). Median ash content for all species ranged from 0.6% to 3.3%. Total wet mass caloric content (kcal g–1) was calculated for the four main species and a linear model was developed for caloric content as a function of moisture. The linear models (caloric content = b0 + b1 × moisture) were Pacific sand lance and Pacific sandfish (b0 = 7.82, b1 = – 0.09); eulachon (b0 = 7.97, b1 = – 0.08); and capelin (b0 = 9.70, b1 = – 0.11).

The role of growth in endocrine regulation of salmon smoltification

Abstract: Keywords: growth, salmon, smoltification, insulin, insulin-like growth factor I (IGF-I), growthhormone, thyroxine, photoperiod, temperature, nutritioncreases hepatic IGF-I mRNA (Cao et al. 1989;Sakamoto and Hirano 1993; Duan et al. 1994) andelevates blood IGF-I levels (Moriyama et al.1994). The majority of IGF-I in salmonid blood isprobably bound to specific binding proteins(IGFBPs), some of which are influenced by GH,insulin and nutrition (Kelley et al. 1992; Siharathand Bern 1993). The IGFBPs in blood and in tis-sues surrounding target cells undoubtedly play asignificant role in modifying the action of IGF-Iin fish, as they do in mammals, although this islargely unexplored in the context of salmon smol-tification. IGF-I inhibits GH release by negativefeedback, as shown