Workshop


The Shrimp Fishery

The shrimp resource was unexploited until 10 small-scale vessels started fishing in 1985. The profit of the first year was very good and already next year 50 small-scale vessels participated in the fishery. The 1986 catch was almost four times the catch of the first year. After 1986 several vessels entered the shrimp fisheries, reaching 100 small-scale vessels by 1987.

In 1988 the first trawlers entered the shrimp fishery when 5 trawlers owned by a foreign company was permitted to fish. In 1989 the government approved a joint venture agreement between a local company and a foreign trawler owner. A new joint venture company entered the fisheries each year up to 1992. At that time indications of overfishing problems could be observed in the catch statistics.

A small-scale fishery project in 1990 resulted in an increase of the small-scale vessel fleet by 50 new participating boats. This was done without any evaluation of the resource consequences.

The current knowledge on the population dynamics of the shrimp stock is poor. Obviously several shrimp species are represented in the fishery, whereby the two most important are the brown and the white shrimp. Reports indicate that seasonal variation is essential in the stock dynamics. Shrimp individuals are growing fast and have short life spans.

The government is very concerned about the development of the shrimp fisheries over the last years, but has poor knowledge on the biology and the economy of the fisheries. Five joint venture companies participate in the fisheries, each paying a certain governmental entry fee per trawler. The fee was in 1994 50,000 US$ per trawler. Some companies are complaining over this being too much in relation to the profitability of the fisheries, and some are considering leaving the fisheries because of that.

The government now want you to evaluate the situation. The companies and the fishing authorities provide catch and effort data and there are good reasons to believe that the data quality is good. The data is presented in table 1.

Table 1. Catch and effort of the Shrimp Fisheries 1985-1994.

Year

Number of small scale vessels

Number

of trawlers

Total catch

(tonnes)

1985

10

0

513

1986

50

0

2023

1987

100

0

3267

1988

100

5

5861

1989

100

15

8009

1990

150

24

10667

1991

150

32

11467

1992

150

43

11413

1993

150

43

9452

1994

150

43

8005

The fisheries has grown fast and represent now a national income of importance. The government therefore has decided to invest US$ 100,000 on the immediate evaluation of the fisheries. This amount of money could be used in different ways to increase current knowledge on the fisheries. Since you are given the responsibility of recommending regulation activities (if any) to be introduced in these fisheries, you are also given the right to decide upon how to use the US$ 100,000.

The different opportunities you have to gain more information are given in table 2.


Table 2. Research reports that could be produced and the costs of producing them (US$ 238 000 all together). 

No.

Reports

Costs

(US $)

 

Biology

 

1

Acoustic survey, stock assessment

50 000

2

Survey using swept area method to estimate present stock size

30 000

3

Theoretical modelling of population dynamics from catch and effort data

20 000

4

Report on population growth based on studies of similar species other places in Africa

15 000

5

Report on mortality rates based on studies of the same species in different areas in Africa

10 000

6

Laboratory experiment and theoretical models of individual growth

10 000

 

Economy

 

7

Inland market price of shrimp products

7 000

8

Export prices of different companies

10 000

9

Report on costs of the fishing activities of the companies

10 000

 

Technology

 

10

Report on selection properties of the different industrial trawlers

30 000

11

Report on selection properties of the small scale vessel gears

20 000

 

Sociology

 

12

Report on the importance of the small scale fisheries on the employment situation

8 000

13

Report on the importance of the small scale fisheries in different regions

8 000

14

Report on the importance of the small scale fisheries on the food supply situation

10 000


The 14 reports contain information that may be important for your evaluation process. You have to make a selection though, since the amount of money is not sufficient to receive all possible information. You do not have to select all reports of your interest at once. A stepwise decision procedure could be preferable.

Final evaluation of your work as an adviser will be conducted after your advice has been followed for a period of five years. The economical benefit from the fisheries plus the amount of the USnbsp;100,000 that not has been used (+ interest over five years) minus the control costs, should be maximised, also taken into consideration the following moments:
  • A very dramatic regulation could force the foreign companies to leave the fisheries for a long period of time.
  • A dramatic regulation of the small-scale fleet could lead to unemployment and social problems in the regions.
  • The importance of the regional distribution of food and fishermen has to be given value.
  • The fisheries should be managed in a sustainable way.
The available management means are given in table 3. Different types of regulation could also be combined if this is preferred.

Table 3. Types of regulation and costs involved.

Type of regulation

Control costs (US $)

Quota of Total allowable catch (TAC)

100000

Limited entry

100000

Closed season (month by month)

10000 each month of closing

Tax per industrial trawler

5000 per trawler

Mesh size regulation

200000

Workshop results

Comments