J. Nat. Aquat. Resour. Res. Dev. Agency 39 (2009)
National Aquatic Resources Research & Development Agency,
Crow Island, Colombo 15, Sri Lanka.
Gillnet selectivity and food and feeding habits of Sphyraena
obtusata and Sphyraena jello in the coastal waters off Negombo,
Sri Lanka
K.A.T. Dananjanie1, M.D.S.T. De Croos1* and D.C.T. Dissanayake2
1
2
Department of Aquaculture and Fisheries, Wayamba University of Sri Lanka.
National Aquatic Resources Research and Development Agency, Crow Island, Sri Lanka.
Abstract
Barracuda is popular with consumers due to its nutritive value and relatively low price
compared to other species such as Seer fish and Tuna. The biology and fishery of
Barracuda, however, have not been thoroughly investigated much and the literature
is scanty. Barracuda by-catches are common in Herring gillnet fishery operations in
the coastal waters off Negombo. Gillnet selectivity of Sphyraena obtusata and
Sphyraena jello and food and feeding habit of Sphyraena obtusata were investigated
over one fishing season from July to November 2006, using these by-catches.
Estimated values for gillnet selectivity of S. jello for 2.5 cm and 3.0 cm mesh sizes were
13.1-26.0 cm and 14.0-25.7 cm while those for S. obtusata were 15.2-25.4 cm and 12.827 cm respectively. Estimated Lopt for 2.5 cm and 3.0 cm mesh sizes were 27.61 cm and
33.12 cm for S. jello and 20.06 cm and 24.06 cm for S. obtusata respectively. Asymptotic
length and growth constant of S. jello and S. obtusata were estimated to be 44.63 cm,
1.51 year-1 and 22.8 cm, 1.00 year-1 respectively. The length weight relationship of S.
obtusata (y = 2.3501x – 1.1387) indicates isometric growth. The estimated relative gut
length (y) and standard length (x) relationship (y = -3E - 05x2 + 0.0008x + 0.3085) shows
that the digestive tract of S. obtusata is morphologically adapted for ontogenetic
variations for food and feeding. Relationship between Gastrosomatic index (y) and
standard length (x) (y = 0.0097x2 + 0.471x + 7.9435) of S. obtusata indicated higher
feeding efficiency in smaller and larger length groups. Different fish species,
crustaceans, molluscs, zooplankton and phytoplankton were found in the stomach
contents. The most common food item was Stolephorus indicus. In multivariate
analysis, food habits were found to be similar in all tested length classes (13 cm to >31
cm) except 13-15, 27-29 and 23-25 cm length groups at 52% similarity level.
Keywords: Barracuda, food and feeding habit, Gear selectivity, Gillnet catch, Population
parameters.
*corresponding author – E-mail: dileepa_dc@yahoo.com
J. Nat. Aquat. Resour. Res. Dev. Agency 39 (2009)
National Aquatic Resources Research & Development Agency,
Crow Island, Colombo 15, Sri Lanka.
Tropical indigenous ornamental fishes of the Western Ghats of
India and the present status of the development of their captive
breeding technology
T.V. Anna Mercy*, Raju K. Thomas and Eapen Jacob
College of Fisheries, Kerala Agricultural University, Panangad,
Cochin, Kerala, India 682506.
Abstract
India has a rich diversity of fresh water fishes in the Western Ghats and North Eastern
Hills. The Western Ghats is the richest region in India with endemic freshwater fishes. It
is one of 34 biodiversity hotspot areas on the global map. It extends from the tip of
Kanyakumari to the River Tapti of South India for a stretch of 1600 km. Studies carried out
under the National Agricultural Technology Project entitled “Germplasm inventory,
evaluation and gene banking of fresh water fishes”, a database of indigenous ornamental
fishes of the Western Ghats (WG) was prepared based on their desirable qualities. Of the
300 species of fishes inhabiting the different river systems of the Western Ghats, 155 are
considered as potential ornamental fishes. Of this, 120 species are endemic to the Western
Ghats. Under the project, 90 species of fishes were collected from the different river
systems of the WG and they were studied for desirable qualities such as nature of
acclimatization in aquariums, compatibility with other species of fishes, food and feeding
habits in captive conditions, level of occurrence in the water column and their behaviour
in aquariums. Based on the results, 85 of them are recommended as ornamental fishes.
Most of them belong to the categories of barbs, loaches, danios, killifishes, hill trout and
catopras.
In spite of the abundance of this rich resource, only a few of them have received the
attention of ornamental fish traders and hobbyists in the global market. This is due to the
lack of awareness of these resources and the lack of a steady supply according to the
demand. The few species exported from India are collected from the river systems in the
wild and sent directly and, as a result, many of the endemic species have now become
endangered. In this context, development of captive breeding technology has great
relevance. So far no serious attempt has been made to develop captive breeding technology
for these rich resources of India. Under the above-mentioned project, captive breeding
technology was developed successfully for 10 prioritized species of ornamentals, which
is the first of its kind in India. They are Puntius filamentosus, Puntius pookodensis,
Puntius melanostigma, Puntius melanampyx, Garra mullya, Danio malabaricus, Chela
fasciata, Nemacheilus triangularis, Nemacheilus semiarmatus and Pristolepis
marginata. The sexual dimorphism, life history stages and water quality parameters and
reproductive strategies are also described in the paper. The technology can be utilized
well for their commercial production in captivity.
keywords: Ornamentals, Western Ghats, Indigenous fishes, Captive breeding
* Corresponding author - E-mail: annamercy2002@yahoo.co.in
J. Nat. Aquat. Resour. Res. Dev. Agency 39 (2009)
National Aquatic Resources Research & Development Agency,
Crow Island, Colombo 15, Sri Lanka.
Post tsunami recovery of fauna and flora of the Barberyn reef,
Beruwala, Sri Lanka
S.C. Jayamanne and D.D.G.L. Dahanayaka*
National Aquatic Resources Research and Development Agency, Crow Island, Colombo 15,
Sri Lanka.
Abstract
Barberyn reef, a reef situated on the South-west coast of Sri Lanka at 6º 26’ N and 79º
58’ E, which was denuded by the tsunami, 2004, was studied to monitor the recovery
of flora and fauna. The site was visited immediately after the tsunami and at periods of
6 months, 1 year and 2 years. A line transect was laid parallel to the shore along the
reef and triplicate quadrate samples were taken from 16 sampling locations at 50 m
intervals. Positions of the locations were accurately noted using a hand held GPS.
Percentage cover of sea weeds and abundance of invertebrates were recorded. The
reef was observed to be almost bare immediately after the tsunami. A considerable
increase of abundance and diversity of seaweeds and invertebrates was observed
from January to June, 2005 and full recovery was observed by June 2005. Species
richness increased from 2% in January 2005 to 12% in June 2005 while average percent
cover of sea weeds increased from 2% in January 2005 to 23.44± 1.56% in 2005 and to
77.81± 27.62% in 2006. Species richness of invertebrates was 0 in January 2005 and
increased to 5.22±3.42%, 2.81±1.68% and 10.56±3.69% respectively in June 2005,
December 2005 and December 2006. Fourteen species of seaweeds under eleven families
dominated by Turbinaria, Caulerpa, Ulva, Jania, Gelidium, Gracilaria and
Sargassum and twenty-seven species of invertebrates consisting of 11 species of
polychaetes, 9 species of gastropods, 16 species of crustaceans, 2 species of
echinoderms were recorded during the present study. It was also observed that the
abundance of invertebrates increased significantly (r = 0.89, p<0.05) with the increase
of percent cover of seaweeds in the reef.
Keywords: Barberyn reef, Sea weeds, Invertebrates, Tsunami
* Corresponding author – E-mail: ddgldahanayaka@gmail.com
J. Nat. Aquat. Resour. Res. Dev. Agency 39 (2009)
National Aquatic Resources Research & Development Agency,
Crow Island, Colombo 15, Sri Lanka.
Biochemical, Microbiological and Sensory assessment of quality
in value added product (Fish soup powder) developed from
marine trash fish Odonus niger
G. Immanuel*, Surgen A. Bright and A. Palavesam
Centre for Marine Science and Technology, M. S. University,
Rajakkamangalam-629 502, Kanyakumari District, Tamilnadu, India
Abstract
One of the important food processing technologies is the processing of low cost fish
species into value added food products. So the development of soup powder from
low cost raw fish Odonus niger (Trigger fish) is the main objective of this study. The
developed food product was subjected to qualitative assessment encompassing
biochemical, biophysical, microbiological and sensory evaluation tests. Two different
combinations (C1 and C2) of soup powder were prepared and aseptically packed and
stored at room temperature. The quality changes were studied for a period of 120 days
at intervals of 15 days. Among the 21 amino acids analysed, levels of isoleucine and
arginine (11.04 to 14.03 g/100 g) were found to be high in both soup powders. Among
the vitamins tested, vitamin C was highest (4.67 mg/100 g) in C1 and vitamin K (9.10
mg/100 g) in C2. Similarly, results on mineral analysis indicated that the quantity of
calcium (695.0 and 702.0 mg/100g) and phosphorous (124.36 and 147.32 mg/100 g) was
high in C1 and C2 products, respectively. The microbial count (TPC) in the samples C1
and C2 increased from 8 to 57 and 11 to 59 x 102 CFU/g respectively, in a storage span
of 75 days, and decreased thereafter. The content of protein, carbohydrate and lipid in
both samples displayed no change during the storage. In contrast, the levels of
TMA-N, TVB-N and FFA increased rapidly in both products with increasing storage
time. The values for pH and moisture slightly increased in both products from initial
to final days of storage. Based on the results of sensory evaluation study, the prepared
soup powder C1 had retained a desirable colour, texture, odour and flavour and was
qualitatively acceptable even up to 120 days of storage; the C2 preparation, however,
maintained its quality only up to 90 days of storage.
Keywords: Trigger fish; Soup powder; TMA-N; TVB-N; FFA
* Corresponding author - Email: gimmas@gmail.com
J. Nat. Aquat. Resour. Res. Dev. Agency 39 (2009)
National Aquatic Resources Research & Development Agency,
Crow Island, Colombo 15, Sri Lanka.
Journal of the National Aquatic Resources, Research and Development Agency
Sustainability and Local People’s Participation in Aquaculture:
Experiences from Sri Lanka and the Philippines
Daniel A. Bergquist, PhD
Uppsala Centre for Sustainable Development, Villavägen 16, SE-752 36 Uppsala,
Sweden.
Abstract
This paper discusses sustainability and local people’s participation in aquaculture,
based on field studies in Sri Lanka and the Philippines. The culture practices studied
are monoculture of the black tiger shrimps (Penaeus monodon) and milkfish (Chanos
chanos), and polyculture of the two species together with mud crab (Scylla serrata).
By using environmental accounting, GIS and PRA methodologies, economic viability,
social equity and environmental impacts in aquaculture are analysed, compared and
discussed to highlight local and regional differences between Sri Lanka and the
Philippines.
Findings indicate that the most significant differences are in the level of participation
by local people and dependence on imported versus local resources. The extent to
which these differences are due to the differing cultural practices applied in the two
cases is discussed. In Sri Lanka, semi-intensive shrimp monoculture is practiced,
which is why cases from extensive shrimp/fish polyculture in the Philippines can be
used to illustrate differences, alternatives, and effects for sustainability. Previous
studies, as well as fieldwork, indicate that extensive culture practices reduce
environmental impacts and benefit local people more. Therefore, it is likely, that
extensive poly-culture practices result in more sustainable and socially equal
aquaculture. Empirical evidence from the field studies is thus not only used for
illuminating regional differences, but also to discuss problems and opportunities for
making future aquaculture development programs in Sri Lanka more bio-technically
feasible, environmentally friendly and socio-economically acceptable than they are
today.
Keywords: Aquaculture, Sustainability, Socio economic effects, Environmental
Accounting, Geographical Information Systems, Participatory Rural Appraisal, Sri
Lanka, Philippines.
* Corresponding author – E-mail: daniel.bergquist@cemus.uu.se
J. Nat. Aquat. Resour. Res. Dev. Agency 39 (2009)
National Aquatic Resources Research & Development Agency,
Crow Island, Colombo 15, Sri Lanka.
Iron content and it's in vitro availability in two fish species;
Sardinella melanura and Carnax spp.
I. Wickramasinghe 1*, K.K.D.S. Ranaweera 1, U.G. Chandrika2, I.D. Wijesinghe3 and A.
Bamunuarchchi1
1Department of Food Science and Technology, University of Sri Jayewardenepura.
2Department of Biochemistry, University of Sri Jayewardenepura.
3Department of Forestry and Environmental Science, University of Sri Jayewardenepura.
Abstract
Iron deficiency is one of the most common nutritional deficiencies in Sri Lanka and is
associated with problems such as poor food supplies and inadequate amounts of available
iron forms in the food consumed. A study was carried out using a modified in vitro iron
availability method, therefore, to investigate the iron content and its availability in two
fish species, namely Sardinella melanura (Salaya) and Carnax spp. (Para), commonly
consumed in Sri Lanka.
The iron content was determined in cooked fish flesh, cooked fish bones and cooking
water using atomic absorption spectroscopy and calculated on a dry weight basis. The in
vitro availability of iron in cooked fish flesh was estimated using the method described
by Svanberg et al., (1993) with some modifications. The data were statistically analysed
using MINITAB.
In cooked Sardinella melanura, the iron content in flesh was 335.3 ± 6.8 ìg/g whereas in
bones, the iron content was 315.3 ± 6.3 ìg/g. In cooking water, the iron content retained
was 25.0 ± 0.7 ìg/g. The in vitro available iron content was 66.2 ± 4.5 ìg/g. In cooked
Carnax spp., the iron content in flesh was 164.8 ± 9.3 ìg/g whereas in bones, it was 101.1
± 8.2 ìg/g. In cooking water, the iron content retained was 15.0 ± 2.1ìg/g. The in vitro
available iron content in cooked fish flesh was 58.9 ± 4.4 ìg/g.
The content of iron in the fish flesh (p<0.05) and fish bones (p<0.05), cooking water
medium (p<0.05) and the total available iron (p <0.05) were all significantly higher in
Sardinella melanura than in those of Carnax spp.
Although there was a considerable amount of iron in these fish species, the iron availability
was found to be relatively low. Both fish bones and fish flesh contain significantly high
amounts of iron. As the cooking water also contains a substantial amount of iron, the
consumption of gravy of the curry along with the fish flesh will increase the amount
consumed.
Keywords: Cooking, Sardinella melanura (Salaya), Carnax spp. (Para), in vitro iron
availability.
*Corresponding author- E-mail: indiraw@sjp.ac.lk
J. Nat. Aquat. Resour. Res. Dev. Agency 39 (2009)
National Aquatic Resources Research & Development Agency,
Crow Island, Colombo 15, Sri Lanka.
Oil dispersion and status of planktonic organisms in Koggala
Lagoon
H.B. Jayasiri* and E.M.S. Wijeratne
Oceanography Division, National Aquatic Resources Research & Development Agency
(NARA), Crow Island, Colombo 15, Sri Lanka.
Abstract
A Bangladeshi merchant vessel, Amaanat Shah, was sunk on 8th September 2006, 9
nm away at 90 m depth off the southern coast. This incident caused an oil spill off
Koggala coast and oil entered into Koggala Lagoon. The aim of this paper is to
present the oil dispersion and its effect on the status of planktonic community of the
Koggala Lagoon comparing with previous data. The oil dispersion in narrow tidal
inlets like Koggala Lagoon is mainly driven by surface currents, where surface wind
drag dispersion is relatively low. The Estuary Lake Computer Model (ELCOM) along
with the lagrangian partial tracking method was used to study oil dispersion
simulations in the lagoon at different tidal periods. The net oil accumulation inside
the lagoon was also estimated due to the residual currents. The planktonic organisms
had been studied in 2004-2005 in the lagoon and therefore a comparison of the status
of plankton community after oil spill could be made.
The model simulations revealed that oil dispersion in the lagoon was relatively larger
on the east side. Abundance and diversity of zooplankton was comparatively low
where oil was accumulated, particularly in the eastside of Madolduwa. Chlorophyll-a
content also decreased up to 1.5 mg m-3 in the same area. High chlorophyll-a content
of 3.5 mg m-3 observed at the lagoon mouth was similar to that recorded in 2004
September.
Keywords: Chlorophyll, Koggala Lagoon, oil dispersion, phytoplankton, zooplankton
* Corresponding author - E-mail: hbjaya@nara.ac.lk