On the effect of Arabian Sea and Indian Ocean sea surface temperature anomaly on the monsoon rainfall of south-east of Iran

Southeast region of the country has hot and dry weather which causes to happen heavy rainfall in short time period of warm seasons and to occur river flooding. These precipitations are influenced by monsoon system of India ocean. In these thesis, It was tried to evaluate the relation between thermal anomaly of sea surface in India ocean and Arab sea which effects on southeast monsoon precipitations of Iran, For evaluation of this happening in southeast, data were collected from 7 synoptic observation stations of Bandar Abbas, Minab, Kerman , Bam, Chabahar, Iranshahr, Zahedan and 17 rain gauge stations during June to September of each year from 1980 to 2010. Rainy days were determine and then some information about synoptic circulation models, maps of average pressure of sea surface, geopotential height of 700hP surface, geopotential height of 500hP surface, temperature of 850 hPa surface, humidity of 700 hPa surface, vertical velocity of 700 hPa surface, vertical velocity of 500 hP and humidity of 2 meters height for 6 systems were extracted from NCEP/NCAR website for evaluation. By evaluation of these systems it was determined that the monsoon low pressure system tab brings needed humidity of these precipitations to this region from India ocean and Arab sea with a vast circulation. It is seen that warm air pool locates on Iran and cold air pool locates on west of India at 800 hPa surface. In a rainy day this warm air transfers to high latitudes and influences the temperature trough of southeast cold air pool of the country. In the middle surfaces of 700 and 500 hPa, the connection between low height system above India and low height system above the higher latitudes causes the low height system above India to be strength and developed. By evaluation of humidity at 2 meters height and 700 hPa surface we observe that humidity Increases in the southeast region. With penetrating of the low height system of India above the 700 and 500 hPa surfaces of southeast of Iran, the value of negative omega (Rising vertical velocity) is increased. In the second pace, it was shown the evaluation of how the correlation between sea surface temperature anomaly in India Ocean and Arab sea influences southeast monsoon precipitation of Iran. For this purpose the data of water surface temperature anomaly of Arab sea and India ocean, the data of precipitation anomaly of 7 synoptic stations , mentioned above, and correlation coefficient among the data of precipitation anomaly and water surface temperature anomaly of Arab Sea, east and west of India ocean were calculated. In conclusion it was shown that the maximum correlation coefficient of precipitation anomaly had belonged to India Ocean in June and no meaningful correlation was resulted in July among precipitation anomaly and sea surface temperature anomaly for three regions, which were evaluated.

Effects of El Niño–Southern Oscillation events on catches of Bigeye Tuna (Thunnus obesus) in the eastern Indian Ocean off Java

The effects of El Niño–Southern Oscillation events on catches of Bigeye Tuna (Thunnus obesus) in the eastern Indian Ocean (EIO) off Java were evaluated through the use of remotely sensed environmental data (sea-surface-height anomaly [SSHA], sea-surface temperature [SST], and chlorophyll a concentration), and Bigeye Tuna catch data. Analyses were conducted for the period of 1997–2000, which included the 1997–98 El Niño and 1999–2000 La Niña events. The empirical orthogonal function (EOF) was applied to examine oceanographic parameters quantitatively. The relationship of those parameters to variations in catch distribution of Bigeye Tuna was explored with a generalized additive model (GAM). The mean hook rate was 0.67 during El Niño and 0.44 during La Niña, and catches were high where SSHA ranged from –21 to 5 cm, SST ranged from 24°C to 27.5°C, and chlorophyll-a concentrations ranged from 0.04 to 0.16 mg m–3. The EOF analysis confirmed that the 1997–98 El Niño affected oceanographic conditions in the EIO off Java. The GAM results indicated that SST was better than the other environmental factors (SSHA and chlorophyll-a concentration) as an oceanographic predictor of Bigeye Tuna catches in the region. According to the GAM predictions, the highest probabilities (70–80%) for Bigeye Tuna catch in 1997–2000 occurred during oceanographic conditions during the 1997–98 El Niño event.

A northern Indian Ocean record of a bopyrid, Parapenaeon japonica (Thielemann, 1910) parasitic on species of penaeid prawns (Penaeus)

A female of Penaeus merguiensis de Man collected from Karachi fish harbour (8 May, 1993) was with a large specimen of bopyrid in its right gill chamber. Since this was the second record (see Tirmizi and Bashir, 1973) of a bopyrid from a species other than Parapenauopsis stylifera H. Milne-Edwards the specimen was examined out of curiosity.

New evidences on the distribution of predatory pelagic sharks in the tuna grounds of the Indian Ocean

Since the commencement of the exploitation of oceanic tuna resources of the Indian Ocean seventeen years ago, the hooked rates for the tuna species have declined in many areas of the Ocean but there are no evidences of such a trend in the case of the sharks. As a result, the percentage composition of sharks in the longline catches and the percentage of the tuna catch damaged by sharks show an increase. Hence there is an urgent need for innovation of the existing longline gear in order to increase the fishing efficiency for hooking the tuna species with a corresponding reduction in its efficiency for hooking sharks. At the beginning of this fishery, hooked sharks were discarded at sea, at a later stage the liver and fins were taken and the carcass discarded and presently the sharks are also brought along with the tuna catch. Though the shark meat has a very low market value it is brought in order to cover up for the declining tuna catches. Thus it has become very necessary to increase the demand for shark meat by developing products or by-products utilizing shark meat and ensuring the successful continuity of the tuna longline fishery. The pattern of distribution of shark species in the time grounds of the Pacific, Indian and Atlantic Oceans and also the predation of hooked tunas by sharks were discussed earlier (Sivasubranianiam 1963, 1964 and 1966). Some contribution to these studies is made in this paper based on new data become available.

Meeting on BOBLME engagement in the International Indian Ocean Expedition 50th anniversary initiative (IIOE-2), Bangkok, Thailand, 17-18 March, 2015

Objectives included; a contribution to understanding large-scale processes affecting the Bay of Bengal Large Marine Ecosystem Project (BOBLME) and it's living resources; and to align with International Indian Ocean Expedition (IIOE-2) (2015-2020) which will extensively explore and study the Indian Ocean to improve understanding of the ocean and coupled climate processes.

Local solutions to challenges of West Indian Ocean fisheries development

The West Indian Ocean is rich in biodiversity and marine resources. This paper gives an overview of fisheries development and resource management in the region. There are many shared issues that must be addressed within countries and at the regional level. These are illustrated by examples from three countries. In Mozambique the issues of lack of information about artisanal fisheries, excessive harvesting of juveniles and conflicts between artisanal and commercial sectors are highlighted. Elements in addressing this include targeted research and decision-making support tools. The challenges faced in Somalia stem primarily from the political instability that contributed to an absence of sound fisheries policy. An example of a highly participatory process to develop the policy provides a model for other countries. In Tanzania, the issue of dynamite fishing was addressed by local communities initiating a program to promote wise use of the resources. There is a clear opportunity for better collaboration and greater integration of fisheries research and management on a regional basis. There is also much to be learnt by the sharing of experiences between countries. This has been initiated by some recently launched regional cooperation projects, but there are still many challenges facing this region.

Length-weight relationship of some marine fish species in Reunion Island, Indian Ocean

The length-weight relationship of 29 marine fish species form Reunion Island (SW Indian Ocean) belonging to 14 families were computed. Data from 5,340 individuals were used for this purpose. Fish were sampled using different techniques, mainly with rotenone poisoning on coral reef flats, beach seine and handlines on shallow coastal bays, and longline fishing in the nearby open sea.

Reproductive potential of Yellowfin Tuna (Thunnus albacares) in the western Indian Ocean

The reproductive biology of Yellowfin Tuna (Thunnus albacares) in the western Indian Ocean was investigated from samples collected in 2009 and 2010. In our study, 1012 female Yellowfin Tuna were sampled: 320 fish on board a purse seiner and 692 fish at a Seychelles cannery. We assessed the main biological parameters that describe reproductive potential: maturity, spawning seasonality, fish condition, and fecundity. The length at which 50% of the female Yellowfin Tuna population matures (L50) was estimated at 75 cm in fork length (FL) when the maturity threshold was established at the cortical alveolar stage of oocyte development. To enable comparison with previous studies, L50 also was estimated with maturity set at the vitellogenic stage of oocyte development; this assessment resulted in a higher value of L50 at 102 cm FL. The main spawning season, during which asynchrony in reproductive timing among sizes was observed, was November–February and a second peak occurred in June. Smaller females (<100 cm FL) had shorter spawning periods (December to February) than those (November to February and June) of large individuals, and signs of skip-spawning periods were observed among small females. The Yellowfin Tuna followed a “capital-income” breeder strategy during ovarian development, by mobilizing accumulated energy while using incoming energy from feeding. The mean batch fecundity for females 79–147 cm FL was estimated at 3.1 million oocytes, and the mean relative batch fecundity was 74.4 oocytes per gram of gonad-free weight. Our results, obtained with techniques defined more precisely than techniques used in previous studies in this region, provide an improved understanding of the reproductive cycle of Yellowfin Tuna in the western Indian Ocean.

Bycatch in the tuna purse-seine fisheries of the western Indian Ocean

Bycatch taken by the tuna purse-seine fishery from the Indian Ocean pelagic ecosystem was estimated from data collected by scientific observers aboard Soviet purse seiners in the western Indian Ocean (WIO) during 1986–92. A total of 494 sets on free-swimming schools, whale-shark-associated schools, whale-associated schools, and log-associated schools were analyzed. More than 40 fish species and other marine animals were recorded. Among them only two species, yellow-fin and skipjack tunas, were target species. Average levels of bycatch were 0.518 metric tons (t) per set, and 27.1 t per 1000 t of target species. The total annual purse-seine catch of yellowfin and skipjack tunas by principal fishing nations in the WIO during 1985–94 was 118,000–277,000 t. Nonrecorded annual bycatch for this period was estimated at 944–2270 t of pelagic oceanic sharks, 720–1877 t of rainbow runners, 705–1836 t of dolphinfishes, 507–1322 t of triggerfishes, 113–294 t of wahoo, 104–251 t of billfishes, 53–112 t of mobulas and mantas, 35–89 t of mackerel scad, 9–24 t of barracudas, and 67–174 t of other fishes. In addition, turtle bycatch and whale mortalities may have occurred. Because the bycatches were not recorded by some purse-seine vessels, it was not possible to assess the full impact of the fisheries on the pelagic ecosystem of the Indian Ocean. The first step to solving this problem is for the Indian Ocean Tuna Commission to establish a pro-gram in which scientific observers are placed on board tuna purse-seine and longline vessels fishing in the WIO.

Predation of tuna longline catches in the Indian Ocean, by killer-whales and sharks

Since the inception of the tuna long line fishery in the Indian Ocean in 1952, an annual average of 10% of the number of tunas and spear fishes caught continues to be damaged by sharks. In spite of the fact that this method of fishing for tunas is also resulting in the exploitation of a significant quantity of the tuna-preying sharks, the extent of the damage by these predators continues to be fairly constant. Quite often the damaged tunas are acceptable to the market, especially for canning. On the other hand report of damage caused by killer-whales, occasional at the beginning of the fishery in the Indian Ocean, has been increasing in frequency each year and since 1960 tuna fishermen have been desperately calling for ways and means of reducing the damage caused by these mammals. Unlike sharks killer-whales do not get hooked on the tuna long line; and tunas damaged by killer-whales are almost always unfit even for canning. The problem of predation by killer-whales exists not only in the whole of the Indian Ocean including the Timor and Banda Seas but also in the Atlantic and Pacific Oceans, especially in the seas around New Guinea, Samoa, Caroline and Marshal Islands. The seriousness of this problem of predation was highlighted at the annual tuna research conference held in Kochi, Japan, in February 1963, and steps were taken to devote considerable attention to this problem.

Occurrence of whale sharks in coastal waters in the Indian Ocean: an interesting coincidence

Salinity, temperature and pressure are parameters which govern the oceanographic state of a marine water body and together they make up density of seawater. In this contribution we will focus our interest on one of these parameters, the salinity: accuracy in relation to different purposes as well as observation technique and instrumentation. We will also discuss the definition of salinity. For example most of the Indian Ocean waters are within the salinity range from 34.60-34.80, which emphasize the importance of careful observations and clear definitions of salinity, in such a way that it is possible to define water masses and predict their movements. In coastal waters the salinity usually features much larger variation in time and space and thus less accuracy is sometimes needed. Salinity has been measured and defined in several ways over the past century. While early measurements were based on the amount of salt in a sea water sample, today the salinity of seawater is most often determined from its conductivity. As conductivity is a function of salinity and temperature, determination involves also measurement of the density of seawater is now more precisely estimated and thus the temperature. As a result of this method the Practical Salinity Scale (PSS) was developed. The best determination of salinity from conductivity and the temperature measurements gives salinity with resolution of 0.001 psu, while the accuracy of titration method was about ± 0.02‰. Because of that, even calculation of movements in the ocean is also improved.

Studies on distribution, diversity and production of macrobenthic fauna in the Chahbahar Bay

The population density, distribution, diversity and secondry production of macrobenthic fauna of the inner Chahbahar Bay were studied through bi-monthly sampling from April 1995 to March 1996. Samples were collected from water near the bottom and sediment at 14 stations inside the Bay and one reference station located outside at the entrance to the Bay. The environmental parameters Such as temperature, water depth, salinity, pH and dissolved oxygen as well as percentage silt-clay and total organic matter of the sediment were measured. The faunal population density and their distribution is discussed in relation to the environmental changes. results obtained indicated both spatial and temporal heterogeneity in faunal distribution of the Chahbahar Bay. The total of 18 groups of macrofauna were identified in all samples. Amphipods formed the dominant group (21%) followed by polychaetes (19%), gastropods (15.7%) bivalves (10.6%) and all other groups (33.7%). Seasonal changes in faunal density is shown in relation to Indian Ocean southwest monsoon,the result of which indicated lower population density during monsoon (June to September) than that of the premonsoon (February to May) and post monsoon (October to January) periods. The numerical abundance of macrobenthos varied from 10260.m2 before monsoon to 5190 m2 during monsoon season. Three dominant groups of macrofauna including polychaetes, gastropods, and bivalves were identified in all collected samples. Indices of diversity, richness and evenness were calculated for these three dominant groups. The Shannon-Weaver information index was used to describe the spatially and temporally variation in diversity of these three major faunal groups. The results exhibited lower faunal diversity during monsoon period. The annual production of two dominant macrofauna species including a species of bivalve, Nuculana acuta and a species of Cephalochordata, Branchiostoma lanceolatum were measured by using age group determination. Furthermore the mean biomass and total annual production of macrobenthic fauna were estimated for the whole studied area. The potential yield of demersal fishery resources (fish and crustacean) then estimated and worked out to be 15360 tons/year asuming 10% ecological efficiency of hypothetical pyramid from 3rd to 4th marine trophic level. Accordingly the annual exploitable demersal fishery resources for the entire Chahbahar Bay was estimated to be 7600 to 8500 tons/year by taking 50 to 55% of the total estimated potential in to account.

The rediscovery of Notopoides latus Henderson in the western Indian Ocean (Crustacea-Decapoda, Raninidae)

The small brachyuran family Raninidae Dana is represented in the Indo-West Pacific region by eight genera, with only some twenty species. One of the least known genera is Notopoides, which contains only a single species. This genus was first described by Henderson (1888) on the basis of material collected by H.M.S. "Challenger" from the Kei Islands, in the Banda sea off Indonesia. There have been no subsequent reports of this species in the ninety seven years since its original discovery. During the course of the study of the benthic fauna off the coast of East Africa, the Fisheries Research Vessel "Manihine" obtained five specimens of this rare species. These new records, collected during a short period of time, indicate that the species is probably not uncommon in this region, which also represents a great increase in its known geographical range. Specimens have been deposited in the collections of the National Museum, Nairobi, the Rijksmuseum van Natuurlijke Historie, Leiden, and the National Museum, Singapore: Catalogue numbers are crust. 1092 ; Crust. D. 28567; NMS. 1972.8.4.1, male of 35x26 respectively.

Proceedings of the Indian Ocean Conference: Forging Unity: Coastal Communities and the Indian Ocean's Future

This is the proceedings of the Indian Ocean Conference "Forging Unity: Coastal Communities and the Indian Ocean's Future". It contains papers, presentations and vision statement of the conference.

A Review of Indian Ocean Fisheries for Skipjack Tuna, Katsuwonus pelamis, and Yellowfin Tuna, Thunnus albacares

Skipjack tuna, Katsuwonus pelamis, and yellowfin tuna, Thunnus albacares, together comprise the most important component of Indian Ocean tuna catches. Catches of these species by Indian Ocean fisheries have been increasing over the last decade and totaled 262,300 metric tons (t) in 1986 (Fig. 1; Table 1). Skipjack tuna was the most important species at 32 percent of the total tuna catch in 1986; yellowfin tuna was the second most important at 25 percent. Skipjack tuna are found throughout the Indian Ocean from the Gulf of Arabia in the north to lat. 40°S (Fig. 2). Yellowfin tuna are also distributed throughout the ocean to about lat. 50�