24. What are marimum sustainable yield and overfishing? What is the condition of the world's fisheries? What responses to declinin
fisheries appear to contribute to overfishing?

Why is it important to know about maximum sustainable yield (MSY)?

To manage human take from the wild, one needs to know how much can be safely taken without

depleting the resource one wants to take from, and without otherwise negatively impacting the

environment. Fishing is no exception. As scientists and managers have discussed how much fish can be

safely taken out of the sea one concept has become a key tool for fisheries management: maximum

sustainable yield (MSY). In order to participate in the debate about fishing limits, one needs to have an

understanding of the basics of the MSY concept. This briefing is aiming to provide this.

Explanation:

What is MSY?

In population ecology and economics, MSY is the largest average yield (catch) that can theoretically be

taken from a species’ stock over an indefinite period under constant environmental conditions. It is

usually measured in tonnes. To have a viable and thriving fishing sector, the size of fish stocks must be

above levels where they can produce the maximum sustainable yield over an indefinite timeframe.

they need to keep water moving over their gills so they seem to have active periods and restful periods instead of undergoing deep  sleep.  they sleep swim

explanation: