Which topic carries the most marks in the QCE Marine Science external exam?

The reef and beyond carries 34.4% of the marks across the 12 QCAA papers from 2020 to 2025, ahead of Managing fisheries on 29.0%.

How are marks split between question types in the QCE Marine Science exam?

Short answer carries 80.9% of the marks and multiple choice carries 19.1% of the marks, measured across 12 papers and 602 marks from 2020 to 2025.

Has the topic balance changed in recent QCE Marine Science papers?

Yes. The reef and beyond moved down 3.2 percentage points, Managing fisheries moved up 6.9 percentage points and Changes on the reef moved down 5.8 percentage points between the 2020 to 2022 and 2023 to 2025 papers.

How many past papers is this QCE Marine Science analysis based on?

12 QCAA external papers from 2020 to 2025, covering 215 questions and 602 marks. 0.5% of those marks carry no dot-point mapping and sit outside the percentages.

QCE Marine Science most tested topics

Across the 12 QCAA Marine Science external papers from 2020 to 2025, The reef and beyond carries 34.4% of the marks against 9.0% for Oceans of the future, so the paper rewards The reef and beyond more than any other topic. At dot-point level 3.1.3.8 carries 4.2% of paper marks, and three of the 95 dot points that the board assesses externally have not appeared in one of these papers. Every percentage below covers the 99.5% of marks that map to a syllabus dot point.

Computed from 12 QCAA Marine Science external papers, 2020 to 2025: 215 questions, 302 question parts and 602 marks.

Unit, topic and dot-point shares below are of the 599 marks that map to a dot point, so each of those tables adds to 100%. 89 of the 302 parts are assessed against more than one dot point, and their 211 marks are divided evenly between the dot points they cover.

What these papers are

Year	Paper	Questions	Marks
2025	Paper 1	27	44
2025	Paper 2	11	46
2024	Paper 1	26	47
2024	Paper 2	11	45
2023	Paper 1	27	46
2023	Paper 2	8	48
2022	Paper 1	28	48
2022	Paper 2	9	55
2021	Paper 1	28	60
2021	Paper 2	7	48
2020	Paper 1	25	60
2020	Paper 2	8	55

Marks by unit

Unit	Share of marks
Unit 3: Marine systems — connections and change	62.0%
Unit 4: Ocean issues and resource management	38.0%

Marks by topic

Topic	Share of marks	Papers it appears in	Years
The reef and beyond	34.4%	12 of 12	6 of 6
Managing fisheries	29.0%	12 of 12	6 of 6
Changes on the reef	27.5%	12 of 12	6 of 6
Oceans of the future	9.0%	10 of 12	6 of 6

Marks by subtopic

Each topic above breaks into the subtopics below, in the same order.

Subtopic	Share of marks	Papers
Reef, habitats and connectivity	18.1%	12 of 12
Coral reef development	11.9%	11 of 12
Coral reef distribution	4.4%	9 of 12
Fisheries and population dynamics	14.2%	10 of 12
Aquaculture	9.5%	11 of 12
Australia’s fisheries management	5.3%	8 of 12
Anthropogenic change	10.6%	11 of 12
Ocean equilibria	10.1%	12 of 12
Implications for marine systems	6.8%	9 of 12
Management and conservation	5.4%	8 of 12
Future scenarios	3.6%	6 of 12

Marks by dot point

Dot-point numbers and wording are QCAA's own. Where a dot point is written as a list, its items run together here separated by semicolons.

Dot point	Content	Topic	Share of marks	Papers
3.1.3.8	Interpret primary and secondary reef diversity data including abundance, species richness, Simpson’s diversity index, evenness and rank abundance, e.g. Whittaker plot	The reef and beyond	4.2%	7 of 12
4.2.1.11	Describe how factors (including sampling techniques, fish behaviour, temporal and spatial movement, life history) affect the reliability of fisheries population data and how this informs fisheries management decision-making on quota and total allowable catch	Managing fisheries	3.4%	4 of 12
4.2.3.2	Interpret evidence from Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES) fisheries reports to determine changes in fisheries practices over the past 10 years, including economic contribution of aquaculture relative to wild catch; the top five aquaculture species in Australia by volume and value	Managing fisheries	2.8%	5 of 12
4.2.3.3	Describe attributes (e.g. resilience, growth rate, feed conversion ratio) of an aquaculture species detailing its life cycle, adaptations, requirements and marketability that would make a species desirable to farm	Managing fisheries	2.8%	6 of 12
3.1.2.8	Explain the process of larval dispersal, site selection, settlement and recruitment of coral species and describe how factors (e.g. currents, bathymetry, substrate, sediment, predation, competition) affect this process	The reef and beyond	2.8%	6 of 12
3.1.3.2	Explain that the habitat complexity (including species diversity, rugosity and percentage coral cover) established by corals influences the diversity of other species	The reef and beyond	2.7%	7 of 12
3.1.3.3	Explain connectivity between ecosystems (including reef, estuaries, seagrass meadows and mangroves) and the role this plays in species replenishment	The reef and beyond	2.4%	6 of 12
3.2.2.5	Describe the effect of ocean acidification on sea water, including that carbon dioxide ( $CO_2$ ) is absorbed from the atmosphere and bonds with sea water, forming carbonic acid ( $H_2CO_3$ ); the acid releases a bicarbonate ion ( $HCO_3^{-}$ ) and a hydrogen ion ( $H^+$ ); the hydrogen ion bonds with free carbonate ions ( $CO_3^{2-}$ ) in the water, forming another bicarbonate ion; the more dissolved carbon dioxide in the ocean, the fewer free carbonate ions are available to marine organisms for making calcium carbonate shells and skeletons	Changes on the reef	2.4%	8 of 12
3.1.3.9	Interpret regional and temporal trends in coral cover	The reef and beyond	2.2%	6 of 12
3.1.2.6	Identify and describe the symbiotic relationships in a coral colony, including polyp interconnections and zooxanthellae	The reef and beyond	2.0%	4 of 12
3.2.1.1	Interpret data from models to determine potential reef futures under various scenarios	Changes on the reef	2.0%	4 of 12
4.2.2.6	Explain monitoring and control of total allowable catch and fixed quotas	Managing fisheries	1.9%	6 of 12
3.2.1.3	Describe the specific pressures affecting coral reefs, i.e. surface run-off, salinity fluctuations, climate change, cyclic crown-of-thorns outbreaks, overfishing, spills and improper ballast	Changes on the reef	1.9%	5 of 12
3.2.1.9	Compare the responses to bleaching events between two regions, recognising that coral cover increases on resilient reefs once pressures are reduced or removed	Changes on the reef	1.8%	4 of 12
4.1.1.2	Explain the criteria (i.e. site selection, networking and connectivity, replication, spacing, size and coverage) used to design protected marine areas	Oceans of the future	1.7%	4 of 12
3.2.1.5	Explain the concept of coral bleaching in terms of Shelford’s law of tolerance	Changes on the reef	1.7%	5 of 12
3.2.2.7	Determine the effect of temperature (uptake) and changes in primary productivity (storage, e.g. biological pump) on the ocean’s capacity to absorb carbon dioxide	Changes on the reef	1.7%	5 of 12
3.2.2.3	Interpret data to determine how increases in atmospheric carbon dioxide influences both global temperature and ocean pH	Changes on the reef	1.6%	7 of 12
3.2.3.3	Explain that the type of carbonate ions and concentration of ions have an implication for the development of shell-forming and skeletal-forming organisms, including hard corals (Scleractinia), coralline algae, molluscs, plankton and crustaceans	Changes on the reef	1.6%	6 of 12
4.2.1.6	Determine the impact of bioaccumulation and biomagnification through the food web into edible seafood, e.g. ciguatera, heavy metals and microplastics	Managing fisheries	1.6%	4 of 12

These 20 dot points carry 45.2% of the paper marks between them. Another 72 assessed dot points share the rest, and 3 of the 95 externally assessable dot points have not been assessed in any of these 12 papers. Content that has not appeared is still examinable.

What has moved between papers

Comparing the 2020 to 2022 papers with the 2023 to 2025 papers, three topics have moved by more than 3.0 percentage points.

Topic	2020 to 2022 share	2023 to 2025 share	Movement
The reef and beyond	35.9%	32.7%	down 3.2 points
Managing fisheries	25.9%	32.8%	up 6.9 points
Changes on the reef	30.2%	24.4%	down 5.8 points

How the papers are built

Short answer carries 80.9% of the marks across these 12 papers.

Question type	Share of marks	Marks	Parts
Short answer	80.9%	487	187
Multiple choice	19.1%	115	115

Verb	Share of marks	Marks	Parts
explain	30.6%	184	60
identify	15.1%	91	52
describe	9.0%	54	21
predict	6.5%	39	13
compare	5.1%	31	10
draw	4.5%	27	7
justify	4.5%	27	9
infer	4.0%	24	8

What these percentages do not tell you

Where to practise

Every topic above links to its own page of real QCAA questions with marking criteria and average scores attached: The reef and beyond, Managing fisheries, Changes on the reef and Oceans of the future. For the full question bank start at QCE Marine Science.

Syllabus and assessment material referenced in this guide is © State of Queensland (Queensland Curriculum and Assessment Authority), licensed under CC BY 4.0. See our QCAA licensing notice. AusGrader is an independent study tool and is not affiliated with, endorsed by, or operated by the QCAA.