The story of Voyage of loggerhead sea turtles with Dr. Polovina and the NOAA research team is here.

This page has the external link with Western Pacific Regional Fishery Management Council.

In September 1989 Dr. Polovina advised anxious lobstermen on the harvest of spiny lobster in the northwestern Hawaiian Islands. “Overfishing is obvious reason for a low catch in this season. But do not worry, it was a temporary event. Lobsters will be back next year” he said.

In 1990 Lobstermen were not happy. Lobsters did not come back!! Dr. Polovina was not only embarrassed but also under pressure from frustrated fishermen. He had to find the real reason of missing lobsters.

He visited Beth Flint, seabird biologist working for U.S. fish and Wildlife Service and told her his story. Her response was not directly related to lobster, but it provided him some clues.

The reproductive success of the Red-tailed tropic bird and the red–footed booby bird significantly dropped since 1985.
“I cannot tell the reason, but I could tell it is not predator, not diseases or not habitat loss either but luck of food might be. The adult birds simply too busy. They fly away from their nest long period of time to catch their favorite food, flying fish and squid. In the meantime eggs and chicks are exposed to scorching subtropical sun and eventually perished." She said.

Marine mammal expert Tim Ragen explained about first–year survival rate of Hawaiian monk seal and he also pointed out that the rate dropped from about 85% in the mid-1980s to about 45% in the early 1990s.

"I cannot tell exact cause of declining, but I have sensed that the decrease of reef fishes and lobsters played role of this trend, because reef fishes and lobsters are main diets of Hawaiian monk seal." He said.

Lobsters, seabirds and monk seals all of them are connected to one way or the other. Dr. Polovina suspected “Something affected entire coral reef ecosystem.” Prior to find out what it is, he needed to estimate the density of reef fishes. Ed DeMartini, a coral reef ecologist, helped him to get that information.

Gary Mitchum, a physical oceanographer at the University of Hawaii, who had traced the linkage between atmosphere and ocean during this period. He noticed several features of ocean. One of them was exceptionally high sea level in the central and eastern North Pacific region. Another is the extension of warm surface water. The intensity and position of the Aleutian low corresponded to both of those ocean features.

Wind and Plankton

In the early 1980s the Aleutian low reached the greatest intensity ever and it brought strong west wind to northwestern Hawaii. Consequently the wind driven current and rough seas had blended deep nutrient-rich waters with nutrient-poor surface waters. Usually this mixture is not happened in midoceanic regions such as the water around Hawaii. However once this phenomenon has arisen, the growth of phytoplankton increases remarkably. Then zooplankton thrives and sustains the abundance of flying fishes and squids. Reef fishes and lobsters also increase their population because they eat planktons during their larval phase.

The Northwestern Hawaiian Islands Marine National Monument is the largest fully protected area in the United States. It has a great diversity of reef environments and provides a variety of habitat to federally protected species, such as green sea turtle, seabirds, endangered land birds and several species of marine mammals.

Although decline in the survival of lobster larvae immediately followed the diminishment of the Aleutian low in the mid-1980s, a low catch would not occurred until the very late 1980s and early 1990s because Lobstermen catch only three to four years old. Same pattern could be applied to monk seal pups, because they will only eat lobsters and reef fishes that are at least several years old. On the other hand the number of seabird chicks declined with fading low, because juvenile flying fish and squid declined in number. Thus the time lag problem is explained.