Judul: Pengelolaan Berkelanjutan Perikanan Rajungan (Portunus pelagicus) di Lampung Timur.
Abstrak: Increasing demand for crab meat export and followed by good prices have been increased fisher preference for capturing the blue swimming crab, Portunus pelagicus (Linnaeus, 1758) in Indonesia. One of potential area for wild catch production of this species in Indonesia was at the East Lampung coastal waters, which is an open coast type with generally slight slope of marine topography. However, biological information of this species was rare. Catches productivity as well as caught crabs sizes tend also to be decreased and might be related to high exploitation rate; so this fishery is required to be managed properly. This study aimed to: (1) describe life history characteristics in reproductive biology; (2) distinguish spatial temporal variation of stock structure; (3) describe population dynamic parameters; (4) evaluate of crab exploitation pattern; (5) arrange management measure options for sustainable management of this crab fishery in East Lampung coastal waters. A comprehensive reproductive biology parameters were analysed based on representative samples, which were collected at landing site and conducted monthly from June 2011−Mei 2012. Spatio-temporal of stock structure was analysed based on sampling at three stratifications area from March 2012−February 2013. These stratification areas consist of S1 (water depth <5 m and <4 nautical mile from the shore line), S2 (water depth about 5−10 m and 4−10 nautical mile from the shore line), S3 was offshore direction, whiles fourth sub-areas (A1−A4) at each stratification. Those sub-areas were decided based on morphological characteristics of shore and coastal land coverage. Thus, the unit area of sampling was noted as S1A1−S3A4. Those above samples were also used for population dynamic parameter analysis. Crab exploitation pattern was investigated by interviewing the fishers and guided by questionnaire during December 2012−February 2013 and June−September 2013. Life history characteristics of this species in this area indicated by: (a) the size of males and females reach gonad maturity 50% (Lm50)were at 98 mm and 103 mm carapace width (CW); (b) female’s Lm75 and Lm95 were at the size 111.6 mm and 126.0 mm CW, while reproductive maturity (Lr50) was at 115 mm CW; (c) berried females (BEF) ovaries have dominated by gonad development stage of III; (d) gonad somatic indexes of nonberried female (NBF) were higher than BEF in each month, except in August, November, and February, indicating multiple spawning in the year; (e) females became double breeding or more in the year as well as high potential for spawning and the value of relative percentage of BEF/NBF above 30% at the size larger than 111 mm CW; (f) the potentially reproductive females at the size 111−170.99 mm and reproductively females at 111−155.99 mm CW. Reproductive pattern was partially spawner and spawning occurred thorough in the year, but it was seasonal-continuous with two peaks season. The first peak of spawning season tends during April−June and the second peak was during September− October/November. Both peaks of spawning seasons vary in BEF abundance and fecundity. Fecundity at the 1st stage of embryonic development with BEF’s size between 91.58−168.00 mm CW was between 229,4682,236,355 eggs (mean ± SE = 926,638 ± 30,975 eggs), linearly and positive
Keyword: East Lampung, Blue swimming crab, harvest strategy, population biology, sustainable management