Growth Performance of the Mangrove Red Snapper (Lutjanus argentimaculatus) in Freshwater Pond Comparing Two Stocking Densities and Three Feed Types

The mangrove red snapper Lutjanus argentimaculatus (Forsskål 1775) is a high value, euryhaline marine fish with potential as a species for freshwater aquaculture. This study evaluated the growth and cost efficiency of the species in a freshwater pond in two experiments with three replications: (a) comparing stocking densities: (1) 0.5; (2) 1; and (3) 3 fish fish•m-2 reared for six months fed three times a day with trash fish to apparent satiation; and (b) comparing feed types: (1) trash fish; (2) moist diet; and (3) formulated dry pellet at a stocking density of 1 fish•m-2 fed to apparent satiation three times a day for seven months. The stocking density (SD) experiment showed significantly higher weight gain, absolute growth and specific growth rate (P<0.05) in 0.5 fish•m-2 SD (184.9 g; 1.04 g•day-1; 2.50%/day) than 3 fish•m-2 SD (172.7 g; 0.96 g•day-1; 2.38 %•day-1). No significant difference was detected between 0.5 fish•m-2 SD and 1 fish•m-2 nor between 1 fish•m-2 and 3 fish•m-2 (P>0.05). Survival rate (SR) and feed conversion ratio (FCR) were not statistically different between treatments (P>0.05), which ranged from 78% to 92% and 5.0 to 5.9, respectively. Cost analysis showed high net returns for 1 and 3 fish•m-2 SD but low in 0.5 fish•m-2 SD. The feeding experiment study showed that feed types significantly affected weight gain, SGR, and SR (P<0.05). Snappers fed with trash fish attained significantly higher mean absolute growth (298.2 g) and SGR (1.81%/day) than those fed moist feeds (232.8 g and 1.61%/day, respectively) and formulated feeds (236.1 g and 1.51%/day, respectively). The survival rate was significantly higher in snappers fed trash fish (93.33%) and dry pellets (94.00%) than fed moist feeds (81.34%). FCR in trash fish, moist and dry pellet treatment was 6.4, 6.3, and 2.7, respectively. Cost analysis showed high net returns for trash fish and formulated pellet fed snappers but low in moist diet feed treatment. Cost-benefit analysis showed the feasibility of mangrove red snapper for freshwater aquaculture at a recommended stocking density of 1 to 3 fish•m-2 using trash fish, moist diet, or formulated dry pellet.

The occurrence of the Lessepsian migrant Lutjanus argentimaculatus in the Mediterranean, (Actinopterygii: Perciformes: Lutjanidae) first record from the coast of Israel

Two specimens of the Lessepsian migrant, the Mangrove red snapper Lutjanus argentimaculatus are reported from the Mediterranean coast of Israel. L. argentimaculatus was first recorded in the Mediterranean in 1979 by a single specimen. Over three decades later and only in the last two years four specimens, including the two reported herein, were recorded. This pattern strongly suggests that L. argentimaculatus has established a sustainable population in the Mediterranean.

PKM Kelompok Budidaya Rumput Laut Kecamatan Bangkala Kabupaten Jeneponto

Seaweed cultivation activities have long developed, but productivity tends to decrease over time due to various environmental factors. Efforts to increase productivity are minimal, both from government agencies and from the community itself. The results of previous studies indicate that the integration of seaweed cultivation can increase the income of seaweed farmers. The main problems of partners include: low productivity due to fish pest disturbance and technical cultivation, poor business management, low income and variations in seaweed growth. The main targets include: (1) increasing income of partner groups through fishing activities; (2) increasing production of partner groups through fostering seaweed cultivation techniques; (3) increasing business productivity through fostering production and business management. The method of approach is to solve problems with group members (partners), namely: counseling, training, piloting, guidance and assistance as well as practical learning (learning by doing). Counseling includes: technical seaweed cultivation, fishing techniques, group management, business management. Practical training: improvement of construction framework for seaweed cultivation, construction of fishing gear, application of fishing technology. Furthermore, assistance and monitoring and evaluation of the success of the implementation of community partnership program (PKM). The results of extension show that the group realizes that the potential of fish around seaweed cultivation has not been utilized properly. The fish around seaweed cultivation can be utilized by using fish trap or gill net. The results of field observations showed that the bubu could not be operated in strong current conditions and caused partial flooding. In addition, the availability of bait is a limiting factor in the operation of bubu. The bait commonly used in catching rabbit fish is silk moss which is present around the rainy season. Fish caught include: rabbit fish, grouper, mangrove red snapper, barramundi. Weather conditions that are less friendly make the fish catches not as expected.