Effect of a fish stock's demographic structure on offspring survival and sensitivity to climate.

Commercial fishing generally removes large and old individuals from fish stocks, reducing mean age and age diversity among spawners. It is feared that these demographic changes lead to lower and more variable recruitment to the stocks. A key proposed pathway is that juvenation and reduced size distribution causes reduced ranges in spawning period, spawning location, and egg buoyancy; this is proposed to lead to reduced spatial distribution of fish eggs and larvae, more homogeneous ambient environmental conditions within each year-class, and reduced buffering against negative environmental influences.

Timecourse of oocyte development in saithe Pollachius virens.

Wild caught North Sea saithe Pollachius virens were monitored for growth, sex steroid profiles and oocyte development pre-spawning and measured for egg size and group fecundity during the spawning season in the laboratory. Vitellogenesis commenced in late October-early November, at a leading cohort size (C ) of c. 250 µm, after which oocytes grew rapidly in size until spawning started in February.

Modelled drift patterns of fish larvae link coastal morphology to seabird colony distribution.

Colonial breeding is an evolutionary puzzle, as the benefits of breeding in high densities are still not fully explained. Although the dynamics of existing colonies are increasingly understood, few studies have addressed the initial formation of colonies, and empirical tests are rare. Using a high-resolution larval drift model, we here document that the distribution of seabird colonies along the Norwegian coast can be explained by variations in the availability and predictability of fish larvae.

Modelling and interpreting fish bioenergetics: a role for behaviour, life-history traits and survival trade-offs.

Bioenergetics is used as the mechanistic foundation of many models of fishes. As the context of a model gradually extends beyond pure bioenergetics to include behaviour, life-history traits and function and performance of the entire organism, so does the need for complementing bioenergetic measurements with trade-offs, particularly those dealing with survival. Such a broadening of focus revitalized and expanded the domain of behavioural ecology in the 1980s.

The Principles of Buoyancy in Marine Fish Eggs and Their Vertical Distributions across the World Oceans.

Buoyancy acting on plankton, i.e. the difference in specific gravity between plankton and the ambient water, is a function of salinity and temperature.

Spatial dynamics of the bearded goby and its key fish predators off Namibia vary with climate and oxygen availability.

Hypoxia [O < 2.0 mL L (87 mol kg)] and severely hypoxic water masses [O < 0.5 mL L (21.