A pilot study of hogfish (Lachnolaimus maximus Walbaum 1792) movement in the Conch Reef Research Only Area (northern Florida Keys)

The largely sedentary behavior of many fishes on coral reefs is well established. Information on the movement behavior of individual fish, over fine temporal and spatial scales, however, continues to be limited. It is precisely this type of information that is critical for evaluating the success of marine reserves designed for the conservation and/or management of vagile fishes. In this pilot study we surgically-tagged eight hogfish (Lachnolaimus maximus Walbaum 1792) with coded-acoustic transmitters inside the Conch Reef Research Only Area (a no-take marine reserve) in the northern Florida Keys National Marine Sanctuary. Our primary objective was to characterize the movement of L. maximus across Conch Reef in the vicinity of the reserve. All fish were captured, surgically-tagged and released in situ during a saturation mission to the Aquarius Undersea Laboratory, which is located in the center of the reserve. Movement of tagged L. maximus was recorded for up to 95 days by three acoustic receivers deployed on the seafloor. Results showed clear diel patterns in L. maximus activity and regular movement among the receivers was recorded for seven of the eight tagged fish. Fidelity of tagged fish to the area of release was high when calculated at the scale of days, while within-day fidelity was comparatively low when calculated at the scale of hours. While the number of fish departures from the array also varied, the majority of departures for seven of the eight fish did not exceed 1-hr (with the exception of one 47-day departure), suggesting that when departures occurred, the fish did not travel far. Future efforts will significantly expand the number of receivers at Conch Reef such that fish movement behavior relative to the reserve boundaries can be quantified with increased temporal and spatial resolution. (PDF contains 22 pages.)

Water Temperatures and Climatological Conditions South of New England, 1974-83

From 1974 through 1983, we conducted monitoring to provide the first long-term, year-round record of sea water temperatures south of New England from surface to bottom, and from nearshore to the continental slope. Expendable bathythermograph transects were made approximately monthly during the ten years by scientists and technicians from numerous institutions, working on research vessels that traversed the continental shelf off southern New England. Ten-year (1974-83) means and variability are presented for coastal and bottom water temperatures, for mid-shelf water column temperatures, and for some atmospheric and oceanographic conditions that may influence shelf and upper-slope water temperatures. Possible applications of ocean temperature monitoring to fishery ecology are noted. Some large departures from mean conditions are discussed; particularly notable during the decade were the response of water temperatures to the passage of Gulf Stream warm-core rings, and the magnitude and persistence of shelf-water cooling associated with air temperatures in three successive very cold winters (1976-77, 1977-78, and 1978-79). (PDF file contains 51 pages.)

Variability of Temperature and Salinity in the Middle Atlantic Bight and Gulf of Maine

Monitoring of the waters of the Middle Atlantic Bight and Gulf of Maine has been conducted by the MARMAP Ships of Opportunity Program since the early 1970's. Presented in this atlas are portrayals of the temporal and spatial patterns of surface and bottom temperature and surface salinity for these areas during the period 1978-1990. These patterns are shown in the form of time-space diagrams for single-year and multiyear (base period) time frames. Each base period figure shows thirteen-year (1978-1990) mean conditions, sample variance in the form of standard deviations of the measured values, and data locations. Each single-year figure displays annual conditions, sampling locations, and departures of annual conditions from the thirteen-year means, expressed as algebraic anomalies and standardized anomalies. (PDF file contains 112 pages.)

Size composition of the catches of the pink shrimp Penaeus duorarum notialis in the shrimp fishery of Sierra Leone

Measurements were taken of size distribution of P. d. notialis collected off Sierra Leone over a period of six months from October 1977 to March 1978. From the frequency distribution curves it is observed that the curves for male shrimps show only one or two major modes, which show prominence between 12.5 and 14.1 cm of total length. Females mostly exhibited size groups with three or four different length ranges and occasional occurrence of 1 to 5 modes. These size groups were observed to show continuous changes. No one group could be said to be permanent. The point of entry into the fishery of male shrimps was found to be at an average total length of 10.5 cm, while females did so at 11 cm. Sex ratios in the different samples were usually 1:1 but in one case the males were more numerous by 2:1 and in four other samples females were significantly preponderent. These departures from the 1:1 ratio may have been artificially created by sorting of the catches on board the ships.

An uncommon period of cold and change of lapse rate in the Rocky Mountains of Colorado and Wyoming

EXTRACT (SEE PDF FOR FULL ABSTRACT): Temperature and lapse rate show extreme departures from mean values for May 1981 through October 1986 at the high-elevation station D1 on Niwot Ridge in the Front Range, Colorado. If the D1 record is accurate, this period may present an opportunity to identify factors that influence temperature at high elevations, but not necessarily at low elevations. This paper focuses on four questions: (1) Is the D1 temperature record accurate? (2) What is the geographical extent of this anomalous cold period? (3) Are there any identifiable contributing factors or physical events relating to this period? (4) Is there evidence of a similar anomalous period in the past?

Decadal hydroclimatic variability in the western coastal United States: temporal and spatial variations in precipitation, streamflow, and lake level

EXTRACT (SEE PDF FOR FULL ABSTRACT): We have analyzed streamflow variations recorded at 15 USGS gauging stations in California during the past 90 years or so. The anomalies (departures from the 1960-1990 mean discharge) of streamflow on annual-to-decadal time scales are strongly correlated with precipitation anomalies in each drainage basin. ... Although causes of the decadal climate (precipitation) variability are not known with certainty, the use of streamflow records may help us understand the relative strengths of moisture sources and shift of the jet stream in atmospheric circulation.