TITLE:
Factors Affecting Japanese Pond Smelt (Hypomesus nipponensis) Stock Trajectory in Lake Kasumigaura and Kitaura
AUTHORS:
Ashneel Ajay Singh, Noriyuki Sunoh, Shintaro Niwa, Fumitaka Tokoro, Daisuke Sakamoto, Naoki Suzuki, Kazumi Sakuramoto
KEYWORDS:
Pond Smelt, Lake Kasumigaura, Lake Kitaura, Phosphorus, Surface Temperature
JOURNAL NAME:
Open Journal of Marine Science,
Vol.5 No.2,
March
30,
2015
ABSTRACT: The Japanese pond smelt (Hypomesus
nipponensis) stock has been observed to fluctuate quite rigorously over the
years with sustained periods of low catch in Lake Kasumigaura and Kitaura of
the Ibaraki prefecture, Japan which would adversely affect the socioeconomic
livelihood of the local fishermen and fisheries industry. This study was aimed
at determining the factors affecting the stock fluctuation of the pond smelt
through the different years in the two lakes. Through exploratory analysis it
was found that the pond smelt had significant relationship with total
phosphorus (TP) level in both lakes. The global mean land and ocean temperature
index (LOTI) was also found to be indirectly related to the pond smelt stock in
lake Kasumigaura and Kitaura at the latitude band of 24°N to 90°N (l).
Both TP and LOTI had inverse relationship with pond smelt trajectory in both
lakes. For both Lake Kasumigaura and Kitaura, TP for the individual lakes and
LOTI (l) were used as independent variables using generalized linear
model and response surface methods for modeling the stock dynamics of the pond
smelt in the two lakes. Model selection was based on significant parameter
estimates (p R2 values. Phosphorus loading is
an indication of increasing anthropogenic activities in the surrounding area
having negative impact on the pond smelt population. When management decisions
are being made regarding pond smelt fishery and sustainability plans in the
Ibaraki prefecture, the effects of TP and LOTI should be taken into account.
Future research needs to be directed towards deeper understanding the
mechanisms by which TP and LOTI affect pond smelt population in Lake
Kasumigaura and Kitaura for more effective management.