Hinweis zum Urheberrecht
Bericht / Forschungsbericht / Abhandlung zugänglich unter
URL: https://epub.sub.uni-hamburg.de/epub/volltexte/2009/1355/
The Somalia inshore lobster resource : a survey of the lobster fishery of the north eastern region [Puntland] between Foar and Eyl during November 1998
Fielding, P.J. ;
Mann, B.Q.
| Originalveröffentlichung: |
| (1999) http://www.iucn.org/dbtw-wpd/commande/downpdf.aspx?id=9834&url=http://www.iucn.org/dbtw-wpd/edocs/1999-088.pdf |
| pdf-Format:
|
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| BK - Klassifikation: |
| 48.68 |
| Sondersammelgebiete: |
| 21.3 Küsten- und Hochseefischerei |
| DDC-Sachgruppe: |
| Biowissenschaften, Biologie |
| Dokumentart: |
| Bericht / Forschungsbericht / Abhandlung |
| Sprache: |
| Englisch |
| Erstellungsjahr: |
| 1999 |
| Publikationsdatum: |
| 05.05.2009 |
| Kurzfassung auf Deutsch: |
| EXECUTIVE SUMMARY
This report contains a scientific evaluation of the lobster fishery along the north-east (Puntland) coast of
Somalia following a four week survey in the area. Because of the limited time frame for data collection
and the logistical and political problems associated with working along the Somali coast, there are
necessarily some limitations in the data. These have been discussed as objectively as possible. Appendix
1 contains the proceedings of the lobster fishery workshop which was held immediately after the end of
the survey. It should be noted that some of the values quoted in the workshop report were based on a
very rapid preliminary assessment of the data collected, and may thus be slightly different to values in
the main report. Appendix 2 is a species list of fish observed by the survey team during the course of
their work. Some of these are new distribution records for the species.
Artisanal fishing has a fairly long tradition among the people of Somalia, although historically fishing
effort has been small and directed at shallow inshore species. After the drought of 1973-74 the
government resettled large numbers of nomadic herdsmen along the coast and trained them as
fishermen. More recently, a number of development projects, some of which have been funded by Non-
Government Organisations, have increased the efficiency, scope and effort of fishing operations, to the
point where some fish stocks now appear to be in danger of over-exploitation. The lobster (Panulirus
homarus) resource that is distributed along the north-eastern inshore coastal area is typical of such a
stock. Initially catches were very good and this resulted in escalating investment in the fishery, which in
turn resulted in increased fishing effort. Eventually catches and catch rates started to decline and there is
now serious concern that the resource may be over-fished. The decline in the lobster fishery has been of
particular concern to Aid organisations attempting to improve the socio-economic conditions of the
Somali people, because of the importance of the lobster fishery in the coastal economy.
Lobster fishing takes place mainly from October-November and February-April, because monsoon winds
make the sea rough during the other months of the year. In the October-November season, lobsters are
caught mainly by means of tangle nets although breathhold divers make a small contribution to the
catches. During February, March and April, traps made of woven sticks are set to catch lobsters and
tangle nets are hardly used. The reason advanced by fishermen for the change in gear type is that the
lobsters do not feed in October/November, and thus do not enter traps, whereas in February-April,
lobsters feed actively and are attracted to baited traps. Lobsters are processed at villages where there are
freezer trucks. The presence of freezer trucks depends on road access to the coast, which is generally
very poor. At processing stations, lobsters are tailed and individual lobsters are packed in small plastic
packets for freezing. All lobsters, regardless of size or breeding condition, are retained by fishermen. The
frozen lobster tails are all exported to Dubai. Lobster fishing takes place in extremely harsh conditions
and fishermen and traders have to contend with great difficulties associated with the physical conditions
on the coast, the climate, the lack of infrastructure and the lack of investment capital.
A survey of the lobster resource along the Puntland coast was commissioned by the IUCN Eastern
African Regional Office, as part of the Somali Natural Resources Management Programme. The
Oceanographic Research Institute, Durban, as a long-standing IUCN member, was contracted to carry
out the survey between Foar and Eyl. The objectives were 1) to assess lobster densities in the main
fishing areas, 2) to collect data on size composition, sex ratios and breeding condition of the commercial
catch, 3) to collect information on effort, gear type and catch per unit effort (CPUE) in the fishery and 4)
to present the collected information to participants in the fishing industry so that management scenarios
could be developed and implemented.
The survey was intended to cover the area between Foar and Eyl. Hijacking and the theft of much of the
diving and boating equipment resulted in the diving team being forced to operate between Dudura and
Barmadobe, a distance of approximately 133km. Two divers searched an estimated 12 185 m2 of reef.
Lobster densities assessed by transect counts and free ranging timed searches were 4 lobsters per 100 m2
of reef area. Diving conditions were extremely difficult throughout the survey and densities may have
been under-estimated. During a 25 minute SCUBA dive, an average of 13 lobsters was seen. The total
lobster stock between Foar and Eyl was estimated at 1 200 600 lobsters or 264 tonnes. However, the
v
estimate is very dependent on the assumptions made about the total inshore reef area along the east
coast of Somalia
The average size of lobsters caught by the commercial fishery was 59mm carapace length (CL) for
females and 62 mm CL for males. The size at which female lobsters became mature was calculated as 58
mm CL and the main breeding season appears to be in October/November. Although the tangle net
fishery appears to catch fairly large lobsters, 52% of females caught were below the size at which they
reach maturity. Sex ratios were generally biased in favour of males (1.3 males for every 1 female),
although one sample from a northern fishing village contained three females for every male.
Length/weight and carapace length/total length relationships calculated for P. homarus in Somalia were
very similar to those in southern Africa.
A unit of fishing effort was difficult to define for a number of reasons. Average CPUE was 34 kg lobsters
per boat per day, and 1.5 kg lobsters per man per day. There were an estimated 1 220 fishermen
between Foar and Eyl and the estimated annual catch was in the region of 280 tonnes. Total stock size
was probably somewhat under-estimated, since it is unlikely (but not impossible) that the total standing
stock is caught every year. All the people interviewed as part of a survey of attitudes in the fishery said
that catches had declined, and most felt that the reasons for the decline were the increasing fishing effort
and the capture of lobsters by foreign trawlers. Most of the people interviewed felt that some form of
fishery management was also needed.
Natural mortality of P. homarus was estimated as being between 0.60 and 0.85 (the death of between
45% and 57% of the population annually from natural causes). Catch curve estimates of total mortality
were between 1.84 and 2.70, with 1.84 probably being the more realistic figure (the annual death of
84% of the population from fishing and natural causes together). In the short to medium term, the yieldper-
recruit for both males and female lobsters would be between 30% and 55% higher if a minimum
size limit of at least 60 mm CL was observed by the fishermen. The decline in lobster egg production to
levels that might endanger the recruitment of young lobsters is much more rapid and occurs at much
lower levels of fishing effort if small (40 mm CL) female lobsters are caught and retained, than if females
are only caught when they have reached 60 mm CL. Current egg production may be only about 10% of
the original egg production before the fishery started, and this could easily result in very few larval and
juvenile lobsters surviving long enough to become part of the fishable stock (recruitment failure). A 60
mm CL size limit on the capture of female lobsters would greatly reduce the chances of recruitment
failure which would lead to the collapse of the lobster stock.
Fishing pressure on the inshore Somali lobster stock is unlikely to decline in the short term. Almost the
entire stock seems to be accessible to fishermen and there appear to be no unexploited areas. The lobster
populations along the Yemen, Oman and Somali coasts probably all constitute a single stock and all of
them are heavily fished. The heaviest fishing occurs during the main reproductive period and small or
egg bearing lobsters are not returned alive to the water. It is suggested that the implementation of a
minimum size limit of 60 mm CL and the return of egg bearing lobsters to the water would have
considerable benefits for both the yield from the fishery and egg production.
During a two day workshop held at the end of the survey (see Appendix) a number of management
options were agreed to by fishery participants. These included the implementation of a minimum size
limit of 60 mm CL, the return of egg bearing lobsters to the water, the setting of a minimum mesh size of
100 mm stretched mesh for tangle nets, and the introduction of escape gaps in lobster traps. The results
of the survey indicate that if these management measures are effectively implemented and enforced, the
lobster fishery along the Puntland coast should be sustainable at the current levels of fishing effort. The
traders that buy lobsters from the fishermen are seen as central to the implementation of any
management measures. |
