Relationship ranging from angling capacity and you can yield at every model
Contour 2b. Matchmaking between N and you can Y (leftover panel) and you will F and you may Y (right panel) datingranking.net/tr/friendfinder-inceleme/ when carrying skill K changes 5000 and you can 25000 in the Schaefer model
Shape 3. Twenty years simulator of number during the inventory N and you may revenue Rev whenever carrying strength K fluctuated. Inherent rate of growth roentgen is ongoing (0.8) and you can an effective = 5.
Contour 4. A: K is constant (15000), roentgen fluctuated from 0.dos due to 1.4 and you may F is actually set-to roentgen /dos. B: K are ongoing, r fluctuated and you will F was set-to lingering (0.4). C: K fluctuated and you will r are constant (0.8). Here, fishing potential are increased from the q and give try split up because of the one hundred.
The brand new bionomic harmony section away from F where Prof =0 within lower inventory peak F eq (low) ( K =5000, roentgen =0.8) and you can highest stock height F eq (high) ( K =twenty five one hundred thousand, r =0.8) regarding reputation one an excellent = 5 was in fact 0.08 and you can 0.66, respectively (Desk step 1). These are comparable to 160 and you will step one 320 (boat*trips) for the fishing skill, respectively, and equivalent to complete (40) travel by the four and 33 ships.
4.dos Movement into the r
Several amass methods was checked-out on the instance whenever carrying capabilities, K , are constant and intrinsic growth rate, r , varies, i.age. assist F feel lingering and you can F end up being roentgen /2 to generally meet changing r .
The newest bionomic harmony area regarding F in which Prof =0 at the reduced inventory height F eq (low) ( K =fifteen one hundred thousand, roentgen =0.2) and you will large stock height F eq (high) ( K =15 one hundred thousand, roentgen =step one.4) on the standing one to a great = 5 and you will b = dos was in fact 0.15 and you may 0.99, correspondingly (Desk step 1). He or she is comparable to three hundred and you may 1980 (boat*trips) during the fishing ability, correspondingly, and equal to complete (40) trips by 7.5 and you may 49.5 boats.
The time group of stock size N , yield Y and you will funds Rev using non-equilibrium design model are given in Shape six. The newest give turned maximum whenever F = 0.52 and that equivalent to complete (40) sail from the twenty six vessels (Figure 4). The gains became restriction whenever F = 0.twenty four hence comparable to full (40) cruise trips from the several boats throughout the condition one to a = 5 (Desk 1 and you may Fig. 8).
Contour 6. 20 years simulation regarding N , Y and you can Rev when K try ongoing (15000) and you may a great = 5. roentgen fluctuated of 0.2 to a single.cuatro but F try set-to 0.cuatro.
The partnership ranging from Letter and Y , and F and you will Y when roentgen ‘s the minimum and limitation out of confirmed range and you may carrying strength K is actually constant try revealed when you look at the Shape 5
Enough time series of stock size Letter , give Y and cash P rof with the active creation model get when you look at the Contour eight. Contained in this means, F varies annual but cannot meet or exceed the top limit add up to this new angling ability invest advance. This situation is the ideal harvest strategy, just like the F reacts on the genuine assets away from seafood the new inventory. It is necessary to let too much fishing effort remain by the closure of your own fishery whenever F might be reduced due to a great low progress standards.
Profile seven. Two decades simulation out-of Letter , Y and you may Rev when K is constant (fifteen one hundred thousand) and a beneficial = 5. roentgen fluctuated regarding 0.dos to at least one.4 and you can F changed appropriately ( F =r/2), but angling capacity are limited 800 (boat*trips).
From the simulator found in the Shape 7, the fresh inventory proportions gradually converged so you can K /2 (=7 five hundred), the brand new inventory dimensions you to definitely achieves MSY. Your situation whenever angling potential exceeds 1 eight hundred (boat*trips) made give restriction (Profile 4). Fishing mortality off 0.7, is the same as a complete entry to angling capabilities of just one eight hundred (boat*trips), which is equal to F MSY (high), and this is comparable to the full quantity of travel by thirty five boats. Angling death F you to definitely generated the earnings maximum ranged having a great . Whenever a great = 5, F = 0.thirty-six (complete trips because of the 18 vessels) generated the gains restrict, if you’re F = 0.31 (complete cruises by fifteen ships) whenever a beneficial = 10, and you will F turned shorter while the a improved (Profile 8).
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