@article{,

title = {The Indo-Pacific humpback dolphin of the Arabian region: a status review},

author = {Baldwin,R.M.,Collins,T.J.Q.,Van Waerebeek,K.,Minton,G.},

url = {https://www.aquaticmammalsjournal.org/index.php?option=com_content&view=article&id=247:the-indo-pacific-humpback-dolphin-of-the-arabian-region-a-status-review&catid=13&Itemid=157},

year  = {2004},

date = {2004-01-01},

journal = {Aquatic Mammals},

volume = {30},

number = {319},

pages = {111-124},

abstract = {Records of Indo-Pacific humpback dolphin sightings, strandings, and museum specimens in the Arabian region were compiled and used to review the distribution and status of this species. Nominal usage of Sousa chinensis (Osbeck, 1765) has been retained as a pragmatic measure, although the species present in the region resembles Sousa plumbea (G. Cuvier, 1828). Little is known about the ecology of this species in the region. Most available information on S. chinensis in the region originates from the Sultanate of Oman, where this species is among the most commonly recorded cetaceans. However, there is no absolute measure of abundance for anywhere in the region and the status of the species is unknown. Distribution is described for the region to include much of the Arabian (Persian) Gulf, Arabian Sea, Gulf of Aden, and Red Sea, but notably excludes the Gulf of Oman. This discontinuous distribution suggests the possible presence of discrete populations within the region. Beach-cast/dead individuals represent nearly two-thirds of all records (n=303) of this species in Oman. Live sightings indicate unusually large group sizes (up to 100 individuals) in the Arabian Sea and Arabian Gulf. Occasional associations with Tursiops sp. and Delphinus capensis tropicalis were documented. Mating behaviour and the presence of calves were recorded in the months of April and May and calves are also reported in June, October, November and December. Threats to humpback dolphins in the Arabian region include incidental capture in fishing nets, coastal and offshore development (e.g. land reclamation, dredging, port and harbour construction), pollution, boat traffic, oil and gas exploration (including seismic surveying), military exercises and biotoxins associated with red tide events. Evidence for historic and current directed catches of S. chinensis is limited, but opportunistic hunting may occur. Intraspecific variation in cranial measurements of individuals from the Arabian Sea coast of Oman fall within relative values found in individuals from the Saudi Arabian Gulf coast. Cranial abnormalities were few. Recommendations are made for conservation management-oriented research focusing on stock identity and status assessments, as well as for monitoring of fisheries bycatch, clearer definition of other threats, continued specimen and sample collection and training of local scientists.},

keywords = {abundance, Arabian Gulf, Arabian region, Arabian Sea, associations, behaviour, Boat traffic, cetacean, cetaceans, conservation, development, Distribution, dolphin, dolphins, ecology, Fisheries, Gulf of Aden, Gulf of Oman, humpback dolphins, incidental capture, military, museum specimens, nets, Oman, pollution, population, populations, Red Sea, status, Stock identity, Strandings, tursiops},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Nitrogen dynamics during the Arabian Sea Northeast Monsoon},

author = {McCarthy,J.J.,Garside,C.,Nevins,J.L.},

year  = {1999},

date = {1999-01-01},

journal = {Deep-Sea Research Part II},

volume = {46},

number = {151},

pages = {1623-1664},

abstract = {This investigation focused on the weaker and less well understood of the two Arabian Sea monsoonal wind phases, the NE Monsoon, which persists for 3-4 months in the October to February period. Historically, this period has been characterized as a time of very low nutrient availability and low biological production. As part of the US JGOFS Arabian Sea Process Study, 17 stations were sampled on a cruise in January 1995 (late NE Monsoon) and, 15 stations were sampled on a cruise in November 1995 (early NE Monsoon). Only the southern most stations (10§ and 12§N) and one shallow coastal station were as nutrient-depleted as had been expected from the few relevant prior studies in this region. Experiments were conducted to ascertain the relative importance of different nitrogenous nutrients and the sufficiency of local regeneration processes in supplying nitrogenous nutrients utilized in primary production.  Except for the southern oligotrophic stations, the euphotic zone concentrations of NO3- were typically 5-10-fold greater than those of NO2- and NH4+. There was considerable variation (20-40-fold) in nutrient concentration both within and between the two sections on each cruise.  All nitrogenous nutrients were more abundant (2-4-fold) later in the NE Monsoon. Strong vertical gradients in euphotic zone NH4- concentration, with higher concentrations at depth, were common. This was in contrast to the nearly uniform euphotic zone concentrations for both NO3- and NO2-. Half-saturation constants for uptake were higher for NO3- (1.7 æmol kg-1 (s.d.=0.88, n=8)) than for NH4+ (0.47 æmol kg-1 (s.d.=0.33, n=5)). Evidence for the suppressing effect of NH4+ on NO3- uptake was widespread, although not as severe as has been noted for some other regions. Both the degree of sensitivity of NO3- uptake to NH4+ concentration and the half-saturation constant for NO3+ uptake were correlated with ambient NO3- concentration. The combined e!ect of high affnity for low concentrations of NH4+ and the effect of NH4+ concentration on NO3- uptake resulted in similarly low f-ratios, 0.15 (s.d.=0.07, n=15) and 0.13 (s.d.=0.08, n=17), for early and late observations in the NE Monsoon, respectively. Stations with high f-ratios had the lowest euphotic zone NH4+ concentrations, and these stations were either very near shore or far from shore in the most oligotrophic waters. At several stations, particularly early in the NE Monsoon, the utilization rates for NO2- were equal to or greater than 50% the utilization rates for NO3- . When converted with a Redfield C : N value of 6.7, the total N uptake rates measured in this study were commensurate with measurements of C productivity. While nutrient concentrations at some stations approached levels low enough to limit phytoplankton growth, light was shown to be very important in regulating N uptake at all stations in this study. Diel periodicity was observed for uptake of all nitrogenous nutrients at all stations. The amplitude of this periodicity was positively correlated with nutrient concentration. The strongest of these relationships occurred with NO3- . Ammonium concentration strongly influenced the vertical profiles for NO3- uptake as well as for NH4+ uptake. Both NO2- and NH4+ were regenerated within the euphotic zone at rates comparable to rates of uptake of these nutrients, and thus maintenance of mixed layer concentrations did not require diffusive or advective fluxes from other sources.  Observed turnover times for NH4+ were typically less than one day. Rapid turnover and the strong light regulation of NH4+ uptake allowed the development and maintenance of vertical structure in NH4+ concentration within the euphotic zone. In spite of the strong positive effect of light on NO2- uptake and its strong negative effect on NO2- production, the combined effects of much longer turnover times for this nutrient and mixed layer dynamics resulted in nearly uniform NO2- concentrations within the euphotic zone. Responses of the NE Monsoon planktonic community to light and nutrients, in conjunction with mixed layer dynamics, allowed for effcient recycling of N within the mixed layer. As the NE Monsoon evolved and the mixed layer deepened convectively, NO2- and NO3- concentrations increased correspondingly with the entrainment of deeper water. Planktonic N productivity increased 2-fold, but without a significant change the new vs. recycled N proportionality. Consequently, NO3- turnover time increased from about 1 month to greater than 3 months. This reflected the overriding importance of recycling processes in supplying nitrogenous nutrients for primary production throughout the duration of the NE Monsoon. As a result, NO3- supplied to the euphotic zone during the NE Monsoon is, for the most part, conserved for utilization during the subsequent intermonsoon period.  },

keywords = {Arabian Sea, depth, development, diel, growth, productivity},

pubstate = {published},

tppubtype = {article}

}