Geographical Trends in Weight and Condition Index of Surfclams (Spisula solidissima) in the Mid-Atlantic Bight

Underestimation of primary productivity on continental shelves: evidence from maximum size of extant surfclam (Spisula solidissima) populations

“…Direct measurements of respiration and filtration rates are not available for surfclams. Consequently, we used a range of general relationships covering the physiological capabilities of most bivalves: 10°C and 20°C respiration curves of Powell and Stanton () with a Q 10 temperature response of 2 (Rueda and Smaal, ), and the high‐gear and low‐gear filtration rate curves (we use high‐gear and low‐gear in reference to the pace of functioning of the two filtration rate curves described by Powell et al, ; the high‐gear curve predicts filtration rates approximately three times that of the low‐gear curve for a given shell length), with a modal temperature relationship well described for bivalves (Hofmann et al ., ; Flye‐Sainte‐Marie et al ., ; Fulford et al ., ) that has a temperature optimum at 18°C and cessation near 0°C and 24°C, consistent with observed physiological responses (Marzec et al ., ). Biological processes such as reproduction, growth rate and maximum size integrate all physiological functions specified in the model.…”

“…] from all simulations using chlorophyll‐ or chlorophyll + phaeopigment‐derived food was approximately 20 mm smaller at 10 yr of age (160 mm versus 140 mm). This difference in length equates to a substantial difference in biomass of approximately 50 g, a 32% lower biomass than observed (weight in g = 8.3 × 10 −5 × length in mm 2.85 ; from Marzec et al ., ).…”

The intermingling of benthic macroinvertebrate communities during a period of shifting range: The “East of Nantucket” Atlantic Surfclam Survey and the existence of transient multiple stable states

“…This nearly stock‐wide shift in range is due to the narrow temperature window between optimal and the upper lethal limit (Munroe, Powell, Mann, Klinck, & Hofmann, ; Narváez et al, ). Consequences of this physiology include lower condition offshore (Marzec, Kim, & Powell, ), declining maximum size ( L ∞ : Munroe et al, ), and a differential distribution of surfclam shell and living surfclams (Powell, Kuykendall, et al, ). In the latter case, a characteristic of recent colonization is living surfclams with little co‐occurring shell whereas the opposite is indicative of habitat abandonment, the timing of which is dependent upon the degree of time averaging (Bizjack, Kidwell, Velarde, Leonard‐Pingel, & Tomašových, ; Flessa & Kowalewski, ; Kidwell, ; Powell & Davies, ).…”

An Overview of Factors Affecting Distribution of the Atlantic Surfclam (Spisula solidissima), a Continental Shelf Biomass Dominant, During a Period of Climate Change

“…Among the potentially important unknowns is the feasibility of temperature-induced offshore movement of the stock because of light and nutrient supply controls on primary production. Surfclams exhibit reduced condition offshore (Marzec et al 2010) and the extent to which this results from declining food supply in the offshore environment remains to be determined.…”