Subtidal Rocky Shores of the North-West Atlantic Ocean

2019 ◽  
pp. 90-127
Author(s):  
Ladd E. Johnson ◽  
Kathleen A. MacGregor ◽  
Carla A. Narvaez ◽  
Thew S. Suskiewicz
Keyword(s):  
Atlantic Ocean ◽  
Rocky Shores ◽  
North West ◽  
The North

Palio dubia (Nudibranchia: Doridina) from the north-west Atlantic Ocean: is its morphology at hatching consistent with settlement one day later?

2010 ◽  
Vol 91 (8) ◽  
pp. 1651-1654 ◽  
Author(s):  
Jeffrey H.R. Goddard
Keyword(s):  
Embryonic Development ◽  
Atlantic Ocean ◽  
Larval Period ◽  
North West ◽  
The North ◽  
Order Of Magnitude ◽  
Size And Morphology ◽  
Mode Of Development ◽  
Veliger Larvae

Hamel et al. (2008) reported that veliger larvae of the nudibranch gastropod Palio dubia settled 1 to 3 days after hatching and that metamorphosis commenced shortly thereafter. This is an anomalously short larval period for a nudibranch described as having planktotrophic development. I examined the embryonic development and hatching larvae of P. dubia collected intertidally from Maine, USA. Veliger larvae with shells 120 μm long and lacking eyespots and propodia developed in 7 days at 20°C from eggs averaging 69 μm in diameter. Their size and morphology were typical of planktotrophic nudibranchs known to have minimum larval periods of weeks to months, and the available evidence does not suggest any other mode of development exists in P. dubia. The larval period of P. dubia is likely an order of magnitude longer than reported by Hamel et al. (2008).

Shallow Water Muddy Sands of the North-West Atlantic Ocean

2019 ◽  
pp. 128-163
Author(s):  
Sarah A. Woodin ◽  
Susan S. Bell ◽  
Jon Grant ◽  
Paul V. R. Snelgrove ◽  
David S. Wethey
Keyword(s):  
Atlantic Ocean ◽  
Shallow Water ◽  
North West ◽  
The North

Age and growth of the scalloped hammerhead shark, Sphyrna lewini, in the north-west Atlantic Ocean and Gulf of Mexico

2007 ◽  
Vol 58 (1) ◽  
pp. 34 ◽  
Author(s):  
Andrew N. Piercy ◽  
John K. Carlson ◽  
James A. Sulikowski ◽  
George H. Burgess
Keyword(s):  
Atlantic Ocean ◽  
Gulf Of Mexico ◽  
Growth Parameters ◽  
Fork Length ◽  
Age And Growth ◽  
North West ◽  
Scalloped Hammerhead ◽  
The North ◽  
The Usa ◽  
Cent Error

The scalloped hammerhead, Sphryna lewini (Griffith & Smith, 1834), is a globally exploited species of shark. In order to gain insight into the life history of this species in the USA waters, age and growth was examined from specimens (n = 307) captured from the north-west Atlantic Ocean and from the Gulf of Mexico. The von Bertalanffy growth model resulted in growth parameters of L∞ = 214.8 cm fork length (FL), k = 0.13 year–1, t0 = –1.62 year for males and L∞ = 233.1 cm FL, k = 0.09 year–1, t0 = –2.22 year for females. The oldest age estimates obtained for this population were 30.5 years for both males and females, which corresponded to FL of 234 cm and 241 cm respectively. Bowker’s test of symmetry and Index of Average Per Cent Error suggests that our ageing method represents a non-biased and precise approach to the age assessment. Marginal increments were significantly different between months (Kruskal–Wallis P = 0.017) with a distinct trend of increasing monthly increment growth beginning in January. When compared to previously published studies, our growth estimates suggest slower growth than populations in the Pacific Ocean but faster growth than previously reported in the Gulf of Mexico.

Seaweeds and rocky shores of the Outer Hebrides

1979 ◽  
Vol 77 ◽  
pp. 141-153
Author(s):  
T. A. Norton ◽  
H. T. Powell
Keyword(s):  
Spring Tide ◽  
Rocky Shores ◽  
Laminaria Hyperborea ◽  
Brown Seaweeds ◽  
North West ◽  
The North ◽  
Sublittoral Zone ◽  
Outer Hebrides ◽  
History Of ◽  
Sodium And Potassium

SynopsisThe Outer Hebrides are oceanic in character, bathed by comparatively warm waters derived from the North Atlantic Drift. The spring tide range is 3·5 m (west coast) and 4 m (east coast).The southern and western coasts include some of the most exposed shores in Britain and the steep rocky shores exhibit species and zonation patterns typical of north-west Britain. The sublittoral zone is mainly rocky and is dominated by beds of Laminaria hyperborea, which are very extensive west of the Uists.The eastern sides of the larger islands are much more sheltered and have numerous sea lochs many of which have great lengths of very sheltered rocky shore, dominated by extremely vigorous growths of fucoid algae, particularly Ascophyllum nodosum. Some of the lochs have extensive ramifications, with localized tidal tidal rapids supporting a rich and luxuriant flora and fauna.The paper reviews the literature on the ecology of the rocky shores, on the seaweeds in particular, and includes a full list of all seaweeds recorded in the islands with their distribution by island. (Two hundred and sixty-four species are recorded and this is about 38% of the British total.) Thus the seaweed flora is rich and diverse; the presence of selected species is discussed.The large brown seaweeds grow very luxuriantly in the Outer Hebrides and have been used by man there for many centuries. The history of this utilization is briefly reviewed. The fucoids and Laminaria spp. were formerly used extensively as a source of alkalis (sodium and potassium carbonates) and iodine. Nowadays very large tonnages of Ascophyllum are regularly harvested for the production of alginates; quantities of cast up Laminaria hyperborea are also used for this purpose.

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