Nursery habitat

Productivity may be measured by density, survival, growth and movement to adult habitat (Beck et al. 2001).

Identification and subsequent management of nursery habitats may be important in supporting off-shore fisheries and ensuring species survival into the future.

This may include kelp forest, seagrass, mangroves, tidal flat, mudflat, wetland, salt marsh and oyster reef.

Biotic factors include: structural complexity, food availability, larval settlement cues, competition, and predation.

Abiotic: temperature, salinity, depth, dissolved oxygen, freshwater inflow, retention zone and disturbance.

For example, pelagic broadcast spawning, one of several spawning strategies known for marine species, occurs when eggs are released into some level of the water column and left to drift among the plankton until the larvae hatch and grow large enough to settle in nursery habitats and become juveniles after metamorphosis.

Pelagic eggs are buoyant or semi-buoyant and will be subject to the currents and gradients at the level of the water column in which they were released.

Plankton surveys at different depths above the spawning grounds of a species can be used to parcel out where in the water column the eggs have been released.

Information on the duration of larval development (i.e. the number of days it takes for an individual to develop into each larval life stage) can indicate how long the species remains in the water column and the distance the species may travel once it has reached a motile life stage instead of passively drifting.

The knowledge of such larval movement capability can inform the likelihood that areas represent nursery habitats.