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Temp: Surf 21°C Bottom 17°C
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Dive type : Recreational, Photo
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Visibility: Average
Water: Salt
Specific gear used
- BCD: Scubapro - Equator
- Boots: Mares - Dive Boot CLASSIC NG 5mm
- Camera: Sony - RX-100 M2
- Regulator: Oceanic - Delta
- Wet suit: Mares - Flexa 5-4-3
- Weights: 8 kg
Recent Divers in Haffkrug
Dive Profile
- 1. Air
- 12L Steel
200 → 70 bar
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- Average depth: 3.3m
Data provided by EOL.org
Species Identified
Asterias rubens Linnaeus, 1758 (common starfish)
This predatory species takes a range of marine prey including other echinoderms , worms and molluscs as well as carrion . It often prizes bivalve shells apart, using the suckers on the tube-feet. Once a small gap has been ...
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This predatory species takes a range of marine prey including other echinoderms , worms and molluscs as well as carrion . It often prizes bivalve shells apart, using the suckers on the tube-feet. Once a small gap has been opened, the starfish inserts the lobes of its stomach inside the shell, and starts to digest the bivalve . This starfish has a good sense of smell, which helps it to locate its prey and avoid predators . Some of its prey species are able to smell the starfish as it approaches and avoid it . The sexes are separate, breeding occurs in spring and summer and fertilisation occurs externally . The early larval stage (called a 'bipinnaria' larva) is planktonic, it transforms into a 'brachiolaria' larva before undergoing full metamorphosis and settling around 87 days after fertilisation . The life-span of a common starfish is between 5 and 10 years . Large aggregations occasionally form, of around 100 individuals per square metre . It is not known what triggers these aggregations .
Carcinus maenas (Linnaeus, 1758) (green crab)
The shore crab feeds on invertebrates including worms, molluscs and crustaceans Small molluscs and barnacles are taken by young crabs . Breeding peaks in summer, and mating can only take place shortly after the female...
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The shore crab feeds on invertebrates including worms, molluscs and crustaceans Small molluscs and barnacles are taken by young crabs . Breeding peaks in summer, and mating can only take place shortly after the female moults; the male finds a female before she is due to moult, and carries her around underneath his body for a number of days . After the moult, copulation occurs. The female creates a cavity by burrowing in the sand; she lays the eggs whilst positioned over this cavity, attaches them to her walking legs and carries them around for several months . After hatching, the larvae are planktonic for 2-3 years. They then settle as young crabs, and reach maturity after around a year .
Mytilus edulis Linnaeus, 1758 (edible blue mussel)
The mussel is a filter-feeder; it filters bacteria, plankton, and detritus from the water . When large beds of this gregarious species form, individuals are bonded together with threads of byssus. Predation is the greatest...
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The mussel is a filter-feeder; it filters bacteria, plankton, and detritus from the water . When large beds of this gregarious species form, individuals are bonded together with threads of byssus. Predation is the greatest cause of mortality; a range of predators take mussels, including dog-whelks (Nucella lapillus), crabs, sea urchins, star-fish, and birds such as the oystercatcher (Haematopus ostralegus) . Although mussels seem fairly defenceless, remarkably they are able to fend off marauding dog whelks and other predatory gastropods; a number of mussels work together to immobilise the predator with bysuss threads . Organisms that attach to mussels, such as seaweeds and barnacles, may increase the risk of the mussel becoming detached by wave action; however, mussels are able to sweep their foot over their shell, which may help to minimise the likelihood of such an organism becoming attached . The sexes are separate, fertilisation occurs externally and spawning peaks in spring and summer . The larval stage is free-swimming and planktonic for around 4 weeks , before settling first on filamentous organisms such as seaweeds . After growing for a while, they detach and drift in the water on a long byssal thread; a mode of dispersal likened to that of young spiders floating through the air on a silk thread . After four weeks or so, the young mussel will have settled again, this time on a mussel bed . Young mussels are thought to have evolved primary settlement on filamentous substrates in order to avoid having to compete with adult mussels . Mussels are host to the pea crab (Pinnotheres pisum), and a copepod (Mytilicola intestinalis), both of which are not parasites, as was once thought, but commensal organisms . Furthermore, mussel beds provide habitats for a variety of marine life, and support higher levels of biodiversity than surrounding mudflats . The biodiversity of the bed increases with its size and age .
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Lars Behnke
Germany
Date: 2015-08-03 - 10:35
Max Depth: 5m Duration: 56mins
Dive with Michael from Nicedive4u
Sandaale, Grundeln, Seesterne, Strandkrabben, Bewuchs an Pfeilern, Seegraswiese.
5 mm Neopren + Thermo shirt ausreichend für 17°C.
8 kg Blei etwas zu viel, aber hilfreich aufgrund geringer Tiefe.