BIO1100 AN INTRODUCTION TO MARINE BIOLOGY
Field/lab session 1: Shore and underwater habitats and biota Dr J A Borg & Prof P J Schembri The Maltese marine environment supports habitats and species that are typical of the central Mediterranean. The shore is a harsh environment, given that this zone is exposed to strong wave action and other extreme environmental factors, which makes living in such a habitat difficult for marine flora and fauna. Rock pools, which form part of the shore environment, are also a difficult habitat for marine species. Therefore, only specialized species that are well adapted for living in such conditions are found on shores, including rock pools. These include molluscs, crustaceans and polychaetes (worms). Underwater, the marine habitats are fully submerged and environmental conditions are more stable. Compared to the shore, there is a greater diversity of species and habitats underwater. Around the Maltese Islands, the shallow seabed below the shore within a depth range of between 0 m and some 45 m, is characterized by a rocky bottom supporting forests of algae, and by sandy bottoms which may either be bare of vegetation or support seagrass meadows. Apart from substratum type, environmental factors such as exposure to water movement (wave action and currents), water quality, availability of light, and biological interactions, influence the occurrence and distribution of marine habitats and the species that live in them. This session will be held partly in the field and partly in the laboratory and aims to introduce participants to the typical biota of lowland Maltese rocky shores and the shallow waters immediately off them and will consist of: 1. A guided walk along the shore to show the characteristic features of local lowland rocky shores, the different shore zones, zonation, key species of each zone and other features and phenomena discussed during lectures. 2. A demonstration of sublittoral shallow‐water habitats as visible from a vantage point above a lowland shore. 3. A general observational exercise carried out to distinguish the different species found on the shore, in rock pools, and just below the shore in the uppermost sublittoral (by wading, depending on weather and sea conditions). Biota will be identified on site or in the laboratory. 4. If weather and sea conditions permit, a dive (for those who are qualified SCUBA divers) will be made in shallow waters (< 10 m – 15 m) to demonstrate sublittoral species and habitats, and collect specimens for later examination in the laboratory. 5. A laboratory session during which specimens of flora and fauna collected in the field will be examined and identified. Notes for participants The class will be divided into groups. Participants must ensure that they wear appropriate clothing especially footwear for walking on the rock and for wading in shallow water; for the latter old trainers or plastic ‘swimming shoes’ would be suitable, but not sandals and the like which do not offer good protection. Note that to observe most shore organisms you need to get close to them so you may have to kneel in shallow water – come prepared to do this (shorts, towel and a change of clothes). If sunny, participants should take precautions to protect themselves from the sun (hat/cap and sun‐
screen cream); in the case of rain, wear a light waterproof jacket. Participants will need a notebook in a waterproof bag appropriate for use on the shore, and writing implements. A strong knife or penknife (for detaching organisms attached to rock) would be useful, as would a camera. Participants who are qualified SCUBA divers may join in the dive to demonstrate sublittoral species and habitats, and collect specimens. Participants are required to bring their own diving gear, including cylinders. Other participants may snorkel, for which they also need to provide their own equipment (mask, snorkel and fins). Participants are expected to respect living organisms. Collection of specimens is to be undertaken strictly under the supervision of staff. Particular care should be taken not to damage or kill species that are rare or endangered and protected species are not to be collected or damaged in any way. Work programme 1. Take note of the different zones of the marine environment pointed out to you. Note the different habitats found in each. Make a sketch of the shore and label the zones and component habitats and supplement with a photograph if possible. 2. Search the shore [Note: You need to get very close to the rock to spot most species – this is a ‘hands and knees’ job and involves wading and possibly getting wet]. Examine and identify (in general terms only) shore organisms that you find. You can pick up individuals and place in buckets half‐filled with seawater for in situ examination or for later study in the laboratory. Put organisms back in their habitat after you have identified them [Note: Be conservation minded – 30 participants picking indiscriminately will significantly impact the biota]. Make an annotated list of the organisms you find by noting the identity of each organism, and where on the shore it came from and especially microhabitat (for example, flat bedrock, under ledge, in crevices, from shallow rockpool etc.). Do not collect vermetids or seaweeds of the genus Cystoseira – these are protected species! 3. Transport any specimens to be taken to the laboratory in the buckets provided, which should be filled one third to one half with seawater and closed with the lid. In the laboratory, gently transfer any living specimens to a sorting tray and cover with seawater. Use the manuals, keys and books provided to identify the plant and animal species you have collected to the lowest taxon possible. Make a list of the recorded species and the habitat from where they were collected/recorded. Common shore animals of Maltese rocky shores
Euraphia
Patella
d
c
Chthamalus
Chthamalus
st
mon
Patella
Patella
ulys
Far left: Osilinus articulatus
Left:
Osilinus turbinatus
Vermetus triquetrus
Melarhaphe neritoides
Gibbula rarilineata
Nodilittorina punctata
Pisania striata
Columbella rustica
OTHER COMMON ANIMALS ON MALTESE ROCKY SHORES
1.
2.
3.
4.
5.
Shell made of eight articulating plates
surrounded by a girdle with conspicuous
alternating light and dark banding.
 Lepidochitona corrugata
Gastropod shell with a hermit crab inside. The
chelae are more or less equal in size, are reddish
and have black tips.
 Clibanarius erythropus
Typical crab (does not live in a gastropod shell);
square carapace of a dark olive green colour with
brown or reddish brown mottling.
 Pachygrapsus marmoratus
Sea anemone; green or grey-green tentacles with
pink or red tips.
 Anemonia viridis
Sea anemone; deep red colour including
tentacles.
 Actinia equina
JAB/PJS 20‐3‐13