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Water quality was monitored weekly for more than a year at 13 sites in six
shrimp-producing estuaries of Honduras bordering the Gulf of Fonseca. Water
quality differences were noted among estuaries, along longitudinal transects of
estuaries, and between rainy and dry seasons of the year. Estuaries influenced
by rivers (riverine) were more fertile and had less capacity to assimilate
greater waste loads than those not influenced by rivers. The Choluteca River
discharged greater quantities of nitrogen and phosphorus to the Gulf than did
the 11,000 ha of shrimp ponds currently under cultivation. Eutrophication
of riverine estuaries increased with distance from the Gulf because of reduced
water exchange with the Gulf. Eutrophication in riverine estuaries was greater
during the dry season when freshwater inflow diminished. No seasonal
differences were seen for gulf embayments. The shrimp industry could take
immediate steps to constrain estuarine pollution and promote management
techniques that reduce waste load discharge to estuaries. Inaction will
probably result in production losses similar to other shrimp producing areas of
the world.
Prepared as an invited paper for Special Session on Shrimp Culture, WAS
'95, San Diego, California.
Tilapia (Oreochromis niloticus) and tambaquí (Colossoma
macropomum) were co-stocked in tropical earthen ponds at proportions of 0,
25, 75, and 100% of each species. Fish were offered a 28% protein pellet. Total
density was 3 fish/m2. After 182 d, mean treatment production
ranged from 2478 to 5120 kg/ha. Total production increased and feed
efficiency decreased curvilinearly as the percentage of stocked tilapia
increased. Feed efficiency ranged from 1.15 to 2.78. Total nitrogen and
chlorophyll a decreased linearly as percentage of stocked tilapia
increased, because of grazing by tilapia on phytoplankton. Mean tilapia and
tambaquí weight ranged from 187 to 325 g and from 122 to
270 g, respectively. Tilapia mean weight decreased curvilinearly, and
tambaquí mean weight increased linearly as the percentage of stocked
tilapia increased. Tambaquí growth was thought to be hindered by
relatively cool water temperatures. The best species mixture was 75% tilapia
and 25% tambaquí. Feed was offered to Penaeus vannamei at a standard rate, half the
standard rate, half the standard rate in addition to inorganic fertilization,
and inorganic fertilization for 8 weeks followed by the standard rate of
feed. Shrimp were stocked at 7.5 fish/m2 in earthen ponds. The study
was repeated during wet and dry seasons. Yield, survival and mean shrimp size
were 294%, 36%, and 177% greater during the wet than dry season. Mean wet
season yield for the 1/2-ration and fertilizer treatment was significantly
greater than the 1/2-ration treatment. Otherwise, there were no significant
treatment differences in yield. Feed conversion was significantly lower in the
normal-ration treatment than in the other treatments. Fertilization had no
effect on shrimp production during the dry season despite increasing primary
productivity. The standard feeding rate could be reduced by 50% during the dry
season without reducing shrimp yields.
The Pond Dynamics/Aquaculture CRSP is funded under USAID Grant No. LAG-G-00-96-90015-00
and by
the participating US and Host Country institutions.
Questions for or about the Aquaculture CRSP? Comments about this site? Email ACRSP@oregonstate.edu.
Estuarine Water Quality and Sustainable Shrimp Culture in Honduras
Work Plan 7, Honduras Study 1
Abstract
Varying the Proportion of Colossoma macropomum and
Oreochromis niloticus in Polyculture
Work Plan 7, Honduras Study 4B
Abstract
Inorganic Fertilization and Feed Reduction in Commercial Production of Penaeus vannamei during Wet and Dry Seasons in Honduras
Work Plan 7, Honduras Study 3A
Abstract
Disclaimers
