Robert E. Loveland

Rutgers, The State University of New Jersey | Rutgers · Department of Ecology, Evolution and Natural Resources

American horseshoe crab populations are imperiled in many locations, with overfishing, loss, and degradation of essential spawning/nursery habitats generally acknowledged to be the most significant factors. Against this backdrop, some have implicated additional local factors as further stressors. Specifically, rack-and-bag oyster aquaculture and bi...

• Horseshoe crab population sizes and trends have been previously studied using surveys of spawning adults and counts of eggs from surface (top 5 cm) and deep (20 cm) sediment samples. The correlations between surface and deep eggs were studied at two locations, Delaware Bay and Jamaica Bay, USA, and the correlations between egg densities and spawn...

Horseshoe crabs have proven adept at locating suitable areas of sandy beach spawning habitat throughout their long geological history. Paleogeographic studies have shown that the most recent period of sea level rise (SLR) has been occurring in Delaware Bay for at least 6,000 years. Comparison of aerial photographs from the 1930s with contemporary s...

The spring spawning by the American horseshoe crab (Limulus polyphemus L.) results in temporally and spatially discrete inputs of eggs onto sandy beaches in Delaware Bay, USA. We tested the hypothesis that seasonal patterns of sediment organic carbon on Delaware Bay beaches is linked to this pulsed input of horseshoe crab eggs. At a location with m...

During spawning events, horseshoe crab eggs are released from the female’s oviducts, and fertilized by one or more males. Eggs are shaped by the female into discrete clutches deposited in nests at depths of 10-20 cm on intertidal estuarine beaches. Distinguishing between fresh eggs and the early developmental stages is obfuscated by the large amoun...

Horseshoe crabs (Limulus polyphemus) are valued by many stakeholders, including the commercial fishing industry, biomedical companies, and environmental interest groups. We designed a study to test the accuracy of the conversion factors that were used by NOAA Fisheries and state agencies to estimate horseshoe crab landings before mandatory reportin...

We assessed the suitability of intertidal habitats for spawning by horseshoe crabs (Limulus polyphemus) at 12 proposed restoration sites identified by the United States Army Corps of Engineers along the shore of Jamaica Bay, a highly developed estuary in New York City. Based on beach geomorphology, we chose to quantify horseshoe crab activity at fi...

In the horseshoe crab mating system, mated pairs are frequently accompanied by unattached satellite males as they spawn on intertidal beaches. Previous studies have shown that males locate females visually using their lateral (compound) eyes, and that attached (mated) males gener-ally have less heavily worn or damaged carapaces than unat-tached mal...

Horseshoe crab Limulus polyphemus eggs are laid on sandy estuarine beaches, and subsequently develop into first instar (trilobite) larvae that emerge into the plankton before settlement. To obtain estimates of early survival, we collected data on the densities of trilobite larvae within intertidal sediments on a beach in Delaware Bay, New Jersey, a...

The distribution, abundance, and dispersal patterns of horseshoe crab (Limulus polyphemus) trilobite larvae were determined from 671 plankton tows taken near a spawning beach in lower Delaware Bay, New Jersey, in 1998 and 1999. In both years, peaks in larval abundance occurred during periods of rough surf (>30 cm wave heights). Planktonic larvae we...

We used results from a survey of horseshoe crab reproductive activity that was conducted in 1999 throughout Delaware Bay to examine the relationship between estimates of spawning females and egg deposition and analyze how that relationship varies with geography, time within a spawning season, beach morphology, and wave energy. We found that beach m...

We studied the effects of heavy metals on the regeneration of walking legs in horseshoe crabs (Limulus polyphemus). The second walking leg was amputated in embryos (stage 20 and 21) and first instar (trilobite) larvae, and the length and morphology of the regenerated appendage was observed after molting to the second instar stage. Regeneration foll...

We examined the effects of heavy metals on the development of horseshoe crabs using bioassays in which embryos at different stages were exposed either continuously or for 24 h. Abnormalities included segment-defective embryos, double embryos, embryos with abnormal eye areas, and no-posterior embryos. In terms of their ability to affect normal devel...

This study asks whether male-male competition and female choice are important in the mating system of sexually dimorphic, adult horseshoe crabs (Chelicerata: Limulidae, Limulus polyphemus L.). Amplexed pairs approaching a beach for spawning are generally accompanied by a number of unattached, sexually mature suitor males. For the amplexed pair, the...

Trilobite larvae of the horseshoe crab Limulus polyphemus L. develop from eggs deposited within intertidal sediments. Most of these larvae emerge from sediments during the summer. We have found that a smaller component of the larval population on a Delaware Bay (New Jersey, USA) beach can delay emergence, and remain alive within the sediments until...

The relationship of body size to mating success was studied in four populations of horseshoe crabs, Limulus polyphemus L., along the east coast of the U.S.A. in the spring and summer from 1986 to 1989. Crabs of both sexes from Great Bay, New Hampshire, were significantly smaller than crabs from three middle Atlantic coast populations: Sandy Hook Ba...

It has been presumed that intertidal spawning by Limulus polyphemus minimizes the loss of egges to subtidal predators; however, this strategy involves considerable risks. Massive beach strandings of adults accompany seasonal spawning migrations of crabs along Cape May in Delaware Bay, (USA). At least 190000 horseshoe crabs, approximating 10% of the...

Horseshoe crab spawning activity is spatially patchy within the Delaware Estuary. This study investigated the importance of geochemical and erosional factors to the selection of breeding beaches. Two sandy beaches in Cape May county, New Jersey, USA, were studied; one beach had been subjected to considerable erosion, exposing underlying peat; the s...

Adult horseshoe crabs (Limulus polyphemus) spawn on sandy intertidal beaches and then return toward the water. Field experiments demonstrated that beach slope was more significant than vision in this orientation behavior. Both blinded and nor mally sighted crabs showed rapid seaward orientation on beaches with a seaward slope of approximately 6°....

A statistical method for generating seasonal egg hatching profiles is applied to the brachyuran crabs Uca pugnax (Smith) and U. minax (LeConte) in New Jersey. Calibration experiments quantified the time course of egg development, using serial egg sampling at 1- to 2- day intervals from marked ovigerous females maintained in cages in the field. Egg...

Zostera marina, Ulva lactuca, Gracilaria tikvahiae, Codium fragile, Ceramium fastigiatum and Agardhiella subulata dominate the macroflora of Barnegat Bay. Benthic macroalgae and eelgrass represent an important source of primary production. As well as supporting epifaunal and epiflora populations, macroflora attract a rich infaunal community and pro...

Pectinaria gouldii (Verrill), which lives for 1 year in Barnegat Bay, New Jersey, constructs over its lifetime a conical tube of increasingly large sand grains, regardless of surrounding sediment characteristics. However, the rate of increase of mean grain size of the tube and the population density of the worm vary with sediment type. The distribu...

Submitted to: Dept. of Biology. Thesis (Ph. D.)--Harvard University, 1964.

1.1. A method of relating oxygen consumption in Mercenaria mercenaria to pumping rates at 25°C and 22% is described.2.2. For specimens of Mercenaria from 5 to 285 g, the relationship between oxygen consumption and total wet weight was predicted by the regression equation: log QO2 = −0·344 log weight −1·023.3.3. The regression equation predicting th...

1.1. Several organs and tissues of the ascidian, Ciona intestinalis, were extracted and their content of 5-hydroxytryptamine (5-HT, serotonin) estimated using a spectrofluorometer.2.2. No 5-HT was detected in extracts of cerebral ganglia, subneural glands, siphon tips or tunic. Endostyles gave a value of 1·67 μg/g wet tissue; hearts, 0·53 μg/g; gut...

1.1. Stimulation of the cardio-regulator nerves of Mercenaria mercenaria normally causes inhibition of the heart. Stimulation of the nerves following treatment of the heart with benzoquinonium, an antagonist of acetylcholine, causes excitation.2.2. This excitation is prevented by 1-methyl-d-lysergic acid butanolamide, a drug which also decreases or...