The paper addresses dive behavior of loggerhead turtles which are threatened species, and are distributed in temperate ocean basins. Within Pacific, loggerheads commonly comprises of two different genetic stocks; a South Pacific stock mainly originating from breeding sites within New Caledonia and Australia, and a North Pacific stock mainly originating from breeding sites within Japan.
Advances within satellite transmitter technologies have enabled researchers to gather geospatial data on loggerheads within different oceanic and coastal regions. This information have offered more understanding on turtle ecology, which have provided a way to explain migration trends during their life stages. Previous findings within the North Pacific Ocean show that, the oceanic stage of a juvenile loggerhead can last for 10 years or more. Throughout the phase, loggerheads forage and migrate along the temperate convergent fronts and productivity which span the whole North Pacific Ocean.
The spatial overlap amid the loggerhead presence and fishery lead to by-catch interactions. These can be statistically categorized as rare events, but the by-catch of loggerheads by long-liners presents a serious concern and US federally mandated requirements try to reduce loggerhead by-catch. The dive behavior of loggerhead has been reported within different areas of the globe’s oceans. The capability to establish the influence or impact of oceanography on juvenile loggerhead dive behavior is, moreover, significant in fathoming by-catch patterns or trends, as spatiotemporal dive changeability or variability by loggerheads can change the likely vertical overlap amid loggerheads as well as shallow/superficial set long-line fishing device/gear.
The records indicate that over 80 percent of the dives took place to depths not more than 5m and with over 60 percent of the time of turtle spent within this depth range. The variability within the dive parameters were observed amid the four 6-hour durations of the day, and with turtles making more dives, and shorter duration dives at day than at night.
Findings from the cluster scrutiny of dive information revealed that turtles displayed four different dive behaviors or characteristics. The C1, C3, as well as C4 dive categories all denoted behaviors where turtles make fewer dives, but to greater depths as well as longer durations. Whereas all these dive categories were alike in this regard or consideration, there were variations within the dive depths as well as durations between them. The C2 dive category is different from the other three categories and represents 6-hour durations when turtles make many short dives in shallow depths. The data indicate likelihood that C2 dive category is a combination of shallow foraging and transit dive behavior.
There are HLSG and KEBR regional dive behaviors. There is seasonal variability within the spatial location as well as dive behavior of the seventeen loggerheads in HLSFG area. Loggerheads spent most of their time within the 0 to 5 m range during the year, but there are alterations within the duration and number of dives probably reflecting oceanographic conditions. Five out of the seventeen loggerheads were noted to have travelled via the HLSFG to KEBR, and with 3 tags transmitting greater than sixty days in the latter area.
The aim of the research was to fathom the possibility use of animals dive data to reduce fishery by-catch. Most of the loggerhead by-catch within the Hawaii-dependent long-line fishery takes place North of Hawaii between January to March and is coupled with specific thermal range (17.5-18.50C). This article is significant in understanding possible effects/impacts of oceanography on animal (loggerhead) dive behavior which can help in future conservation. Moreover, fill the information gap of by-catch in an effort to reduce extinction of loggerheads through long-line fisheries within the North Pacific.
