Vert-pre et al. (1) identified regimes in productivity for marine fish stocks, with the goal of urging management to develop strategies that are robust to regime-like behavior. Identification of drivers of productivity [i.e., is the stock driven by spawning biomass (the abundance hypothesis in Vert-pre et al.’s analysis in ref. 1) or environment (the regimes, random, and mixed hypotheses)?] is ...

Length-based analyses were conducted to assess the stock of the green tiger shrimp Penaeus semisulcatus. Monthly carapace length frequency data were collected from commercial catches at two main landing sites on the Yemeni Red Sea coast for eight months. Growth parameters, mortalities, exploitation rate and yield per recruit were estimated for this species in this area. The estimated growth par...

Length-based analyses were conducted to assess the stock of the green tiger shrimp Penaeus semisulcatus. Monthly carapace length frequency data were collected from commercial catches at two main landing sites on the Yemeni Red Sea coast for eight months. Growth parameters, mortalities, exploitation rate and yield per recruit were estimated for this species in this area. The estimated growth par...

Abstrac t— Predicting and understanding the dynamics of a population requires knowledge of vital rates such as survival, growth, and reproduction. However, these variables are inf luenced by individual behavior, and when managing exploited populations, it is now generally realized that knowledge of a species’ behavior and life history strategies is required. However, predicting and understandin...

Spawning salmon create patches of disturbance through redd digging which can reduce macroinvertebrate abundance and biomass in spawning habitat. We asked whether displaced invertebrates use non-spawning habitats as refugia in streams. Our study explored how the spatial and temporal distribution of macroinvertebrates changed during a pink salmon (Oncorhynchus gorbuscha) spawning run and compared...

Forecasts of the future abundance of western Atlantic bluefin tuna (Thunnus thynnus) have, for nearly two decades, been based on two competing views of future recruitment potential: (1) a "low" recruitment scenario based on hockey-stick (two-line) curve where the expected level of recruitment is set equal to the geometric mean of the recruitment estimates for the years after a supposed regime-s...

Spawning stock biomass (SSB) is one of the most common measures of stock status. However recent research on reproductive potential has shown that alternative variables may be an improvement over SSB. In the case of European hake (Merluccius merluccius), it is known that large individuals produce more eggs by unit of body weight, and their quality is better than those of small individuals. Under...

The objective of U.S. fisheries management, as mandated by National Standard 1 of the Sustainable Fisheries Act of 1996, is to maintain fish stocks at levels sufficient to produce maximum sustainable yields (MSY). Mandated levels of fishing may be less than MSY but are not to exceed these levels. MSY, of course, has been a highly elusive goal (Larkin 1977). Operationally, National Standard 1 ha...

Drastic changes in both ageand length-at-maturity of cod (Gadus morhua) on Flemish Cap have been observed during this decade. In the present paper, growth by cohort in this period was analyzed and compared with the observed trend in maturation. Different cohorts displayed different growth rates, the strongest 1990 year-class showing fastest growth. The compensatory response to lower population ...