Stock Identification

These flashcards cover key concepts and definitions related to stock identification, species concepts, population dynamics, and fishery management from the lecture notes.

What is a species according to the biological species concept?

Groups of actually or potentially interbreeding natural populations, reproductively isolated from other such groups.

Define 'population' in a biological context.

A community of organisms of the same species, living in a geographical area, that can interbreed.

What are intrinsic parameters in fish stock assessment?

Growth, recruitment, natural mortality, and fishing mortality.

What are extrinsic factors traditionally ignored in stock assessment?

Immigration and emigration.

What does the term 'holistic stock identification' refer to?

An integrative approach considering distribution, dispersal, geographic variation, and population inference.

What role does genetic analysis play in stock identification?

It helps identify genotypic differences to determine potential separate fish stocks.

What is the significance of meristic characteristics in fish stock identification?

These are useful for identifying phenotypic differences such as fin ray and gill raker counts.

Why is population structure important in fishery management?

Ignoring population structure can mislead management decisions, leading to overfishing and depletion.

What are the three assumptions made by conventional stock assessment models?

Closed populations, homogenous populations, and well-mixed populations.

What can cause misaligned management units in fisheries?

Resource and fishery trends leading to large consequences and potentially misleading assessments.

Define 'fish stock'.

Sub-populations of a particular species of fish, traditionally regarded as significant for stock dynamics.

How can geographical variation affect fish stocks?

Location factors such as water quality and depth influence growth, mortality, and longevity.

What type of migration is defined as a long-distance return trip for fish?

Migration, which can be reproductive, feeding, or climatic.

What does 'spatial complexity' in stock definition refer to?

Stocks often overlap spatially and can be defined by geographic features or habitat.

What is a potential problem when using mark-recapture studies in stock identification?

Recapturing fish can be difficult, and mixing rates may not accurately reflect stock separation.